Just when I was giving up hope of a reply (yeah I know off road forum) but thanks wolfie, plenty of insight there for me and I'll add a set of them to the things to test list
I've been running Schumacher carpet dragons the last wee while indoors on carpet and they grip well, last ages and work without messing about with additive which suits me fine but damn they are a big tire. On inch up wheels to remove the slack I'm on 67mm OD which buggers up the roll centre's alot.