I am new to RRS and have just noticed that after not using the car for 3-4 days it has dropped down to access height from on road height, when I start the engine it goes back up again, there are no warning lights on the dash, do I have an air leak, I still have 6 months RAC warranty

Perfectly normal, so long as it goes up evenly again. Always best to lower it to access height to preserve battery life if leaving the car for more than a couple of hours - lowering puts all the electrics into “sleep” mode rather than keeping them in “standby” mode looking for your key fob. 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

As you've got a warranty get it fixed, you have got an air leak (ok it's a minor one, but air leaks only get worse..) the car technically shouldn't go down if left for year, but to put it into context, my 06 sport can be left for 2 weeks and not drop.

It could be a cheap fix and just need a pipe tightening or it could be something more expensive like a leaking air bag or valve block.

You've got a warranty, use it

Thanks Socast, I have booked it in for repair

or the seals in the values could need cleaning/replacing. (£17 on ebay)

You can remove a 20A fuse from under the bonnet before you leave it parked up. (this will stop it self leveling)
If one corner/end is down when you come back to it, it can give clues as to where the problem is.

Worth be worth doing before you let a garage f**k it up

Thank you Andy