Got a pair of 07 RS totems solo air variant. Had them for just over a year. Sgot replaced maybe about 10-11 months ago? Got a couple of scratches on the stanchions, one repaired with smooth sandpaper/nail varnish the other not worth the effort as its too shallow and wide.

Rode at the forest of dean at the weekend and it was lovely n wet. thought my forks had too much air in them as they felt a bit hard. looking back this could have been slow rebound packing the forks down.
washed the bike today and hopped on it for a quick pedal up n down the road and the rebound felt much slower than it should be.
Could this be water affecting the rebound etc? I did change the oil a few months back as I wanted to see if there was anything stuck in the wiper seal scratching the stanchion, haven't felt anything untoward till now with the rain.

Going to morzine on the 15th August.
Do I get them serviced? Do I need them serviced?

Sounds like they could be in need of a simple lower leg service. Drop the lowers off and see what muck you've accumulated in there. If that don't cure it, it might be wise to send em off for a proper look at.