Basically, car is starting to not want to start.

 

Started fine Sunday morning at 5am, drove to work and left in car park.  Came to drive home at 5pm, and it wouldn't start (eventually did after flashing all the trip lights like it is low on battery)

 

Yesterday around 10am it really did not want to start but again eventually it did.

 

Just put a multimeter across terminals whilst it was just idling (900RPM ish) and I get

 

14.10V with engine on, slightly lower than the 14.40V expected from alternator

12.75V with engine off but this drops around 0.01V every 10 seconds until around 12.70V when I removed multimeter

 

I am thinking it is the battery not holding as much charge as it used to as it does look like the original 8 year old battery (and I cannot find any receipt for a new one).

 

Once it eventually started, I can turn the engine off and it will start first time again so could it be that it does not have enough cranking power for cold start?

If it's the original battery, it will have a VW group part number on it. Most people wouldn't replace with a genuine battery, so if it has such a part number, it probably is 8 years old and due for replacement.

If your multimeter has a dc amps current range, you could check for current drains to rule out that possibility.  There's probably loads of videos on youtube about how to do this, if you're not sure. I remember seeing an "Eric the car guy" one a while ago.

Battery defo is at fault, if over 6yrs old get a new one.......................fit a proper one from Bosch/Varta .get from Euro car parts or carparts4less...............

12.75V with engine off but this drops around 0.01V every 10 seconds until around 12.70V when I removed multimeter

 

It's more important how many amps are being sucked with the engine turned off and the car locked. Can you check this with your multimeter?

start with a non rapid battery charge with a good charger  and see how it goes from there 

Checked current drain with multimeter I'm series and had nothing showing on the 10A so very small drain if any.

Went to ecp and got a high power/crank excide battery for £61 and lost a 10mm socket bit when fitting :(

Fitted now so will hopefully solve all problems

Sounds like the alternator was charging.

Assuming your battery light comes on and goes out you should be good.