What is the correct idling speed ? As mine rises to 975rpm after sitting at 750-800 for 30-40 secs. Is this normal?

If it's doing a regen it'll raise the idle speed to a little under 1000 rpm to get the exhaust hotter. Does it happen when you're in stop-go traffic for long periods - it's normal in this case, but if you drive a lot in those conditions your particulate filter (DPF) will clog up. Normal idle speed is somewhere around 750 rpm. If it does this every time it might be running faster to draw extra power for the air conditioning or mirror/window demist/seat heaters or other power hungry items. It also may mean you've got a faulty pressure sensor on the DPF or that the DPF is clogged.

Do quite a lot of miles in her so can't see it being the DPF being clogged, my need a visit to Skoda if it's a sensor as its still under warranty till the end of January

Ours runs at 900 when its moving and out of gear and drops to 750 when its stationary. In the 3500 miles we've traveled since we bought it, it's regenerated just twice.

How does one know when it is regenerating if that's th correct word for the process ?

The revs at tick over will be around 1000rom, the stop/start is disabled, when you turn the engine off the cooling fans keep running, and you'll certainly smell it - like something burning, which of course it is.

I think mine regenerates more than you realise as it can happen during longer journeys and the only way of telling then is if you stop for any reason, keep driving and you don't know. 

Mine seems to sit at 1000rpm nearly all time is this something to worry about ? Should I get it seen to ? Off to Austria in 10 days don't really need any problems.

I think it also depends on battery load, so if you've got the air con on, heated seats on, rear window heater element on, etc it keeps the idling revs up until the battery is recharged fully. I see your location is Birmingham, do you do lots of stop/start short journeys which might lead to the battery not getting up to full charge.

Try giving it a run for 20-30 minutes up the motorway and see what speed it idles at immediately afterwards, if it's still high turn off any electrical equipment and see if that makes a difference. Maybe get the battery checked somewhere to make sure it isn't about to fail.

The other option is to get the codes read to see if it flags anything up, someone with VCDS in your area might be willing to help, have a look here for Briskoda members with VCDS https://www.google.com/maps/d/viewer?mid=zQlwUpVpfeKA.kRFfm1Y0IXQ0&msa=0

Mine also sits just under 1,000rpm until the temperature gauge reaches 90 degrees.

 

I can drive over 5 miles before the coolant peaks, each junction I get to sees the high idle.