Gammyleg

How old is the battery? Sounds like it could be on the way out.

Was the transmission in manual or drive when the video was shot? I'm guessing manual as the transmission would normally shift up to 3rd well before 5k rpm if in drive. In manual it will still upshift to 3rd when it gets close to the red line revs. Either way, something is seriously wrong, and I'm not sure why you haven't returned it for a refund. Of course you may have got an exceptionally good deal on the purchase price.

Would be very interested in what you find and what action, if any, is needed to fix it. Although by the sound of it, it may have fixed itself. Based on the symptoms listed in your first post I'd be very surprised if the clutch pack is responsible. More a software/TCM glitch caused by the battery/non start scenario.

Methylated spirit has always worked for me.

I thought the spiral warning symbol was for glow plugs.

Get yourself something like this to check whether the head gasket has gone pop. https://www.amazon.co.uk/Block-Tester-Bt-500-Combustion-Leak/dp/B06VVBSFTF/ref=asc_df_B06VVBSFTF/?tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=1637813912064832664&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006886&hvtargid=pla-2281435177418&psc=1&mcid=1fdade9073cd38bfb253b430a031dd37&th=1&psc=1&hvocijid=1637813912064832664-B06VVBSFTF-&hvexpln=74&gad_source=1

It would be odd that Skoda fit sensors for options that are not fitted. That said, the Superb is fitted with some rear light clusters with no bulbs in.

Looks like maybe solenoid valve 3 is defective. The only fix would be to get the Mechatronic refurbed which will set you back about £700 ish, or a couple of £ 000 for a new Mech unit which will need coding to your car. TBH, as you've only just bought the car I'd be tempted to return it for a refund, obviously not fit for purpose.

I've had the same air quality sensor fault since I got my car 4 years ago. Personally I don't think it's worth fixing, just another unnecessary gadget IMO.The alternative solution would be to press the recirc button. How hard is that?

https://www.borgwarner.com/aftermarket/diesel-cold-start-ignition/pressure-sensor-glow-plugs Mine was also changed as a full set. The pressure plug was only £70, but that was 6 years ago.😁

This thread may be of interest. https://mhhauto.com/Thread-DQ200-0AM-DSG7-mechatronic-software-interchangeability?page=6

This is totally normal behavior. One question, have you tried driving in D but selecting Sport mode. This will cause the gear changes to extend well beyond the normal rev range and could influence whether the judder appears or not.

Sounds very similar to my DQ200 however mine will slip rather than judder. Like yours it's intermittent and it improves/disappears when driving in manual mode. Temperature seems to play a part but I can't identify any specific trend between hot and cold, dry or damp. I also have a suspicion that engine loading plays a part but have not found a way to investigate further. I suggest the following in this order: Find someone with a VCDS who knows how to interrogate the transmission system. My money is on a solenoid valve problem in the Mechatronic which may be sticking due to the lack of oil changes in the DQ200. ( Skoda say it's not needed, my 180k mile DSG oil change would beg to differ ). A VCDS showing live data can compare pressures needed vs pressures delivered to the valves along with lots of other useful information, but again you need someone who knows what their looking at....which isn't me by the way. If one is available, get the transmission software updated at your Skoda dealer. It may not solve the problem but would hopefully change the way your DSG shifts between gears and could prove that the 2nd gear clutch is actually OK. I had mine done but if anything it made it worse as the slipping became evident during other gear changes after the upgrade. Cost of an update should be about £100, hence this is one of the first things to try. Next thing would be to get the Mechatronic and transmission oils changed. As mentioned above, this is deemed unnecessary by Skoda, but that's total BS. No oil will last forever and it's a relatively straight forward and cheap process to get done. The only downside is that you can't change the Mech oil filter unless to strip down the unit to get to it and I wouldn't recommend that unless you get a repair kit with new gaskets and seals for reassembly. Cost for my oil change was £38.59 for the oils ( there a two ) + £75.00 labour. Next option would be to have the Mechatronic reconditioned. There are companies that will run benchtop diagnostics on the unit and hopefully identify what the problem is. Your symptoms do point to a bad solenoid IMO but they would be able to confirm. Downside is that you'd have to get the Mech unit removed and posted to the re-manufacturing company so you'd be without a car for a couple of weeks. A special tool is required to remove and refit the Mech from/to the transmission, it's not too expensive but it's only function is just that. Cost of a refurb in UK starts at about £700. Lastly if all of the above have failed, you may need a new clutch pack. Cost of this for me was £391 for the clutch, £323 for a new flywheel. The flywheel may not be needed but as the clutch is getting done it's saves repeating the biggest cost of the job which was £500 ( 10hrs ) labour. The new clutch pack has done absolutely nothing to fix the problem but did manage to drain my bank account by a tidy sum so this is why I'd carry out this step last. Now I didn't follow the steps above in the order in which they are listed and consequently still have an bad DSG. I don't know anyone who knows much about VCDS so point 1 has still not been carried out successfully. Points 2, 3 & 5 have been done and I still have a bad box.

Answers to both are probably contained within the pinned post at the top of this forum page.

Possible match but for some reason the Castrol spec misses the 'A2' ref at the end of the specification. Not sure if that's is an issue or not.

I believe that the speedo can be recalibrated with a VCDS, however the method is well above my pay grade.

Heaven forbid that a garage would rip you off, particularly as it seems that the OP has limited knowledge of available options. Your comment seems to call into question the whole purpose of this forum.

I would suspect it allows water to flow out rather than in. Is it not a drain hole?

Warped disc maybe.

I tried on the way home last night, took it up to about 4000rpm in 1st and then again in 2nd but no sign of an upshift. I wasn't keen on taking it any higher as it was only a couple of minutes after initial start-up and oil/water etc was still cold.

You should find loads on eBay. A fair bit cheaper but I can't vouch for the quality though.

That's as registered outside the vehicle rather than inside the cabin. My previous Dunlop SportMaxx2s are listed between 68 - 70db and were quite noisy. Current Michelin CrossClimate 2s are listed as 69-71db and are MUCH quieter. Go figure!

I use something called a foot. Works every time and reacts just how I want it to.

Maybe the pollen filter needs changing. You could take it out and have a sniff.