If you remember Dave I posted a picture of a 5 shot group I did with the platinum when I first got it, they where the first shots through the rifle after it had been set-up and straight from the tin (AA 4.52) one hole.
The group opened up after a little while, I switched to exact express and again got one hole groups.
After switching batch because I wasn't able to get any more in the batch I had the rifle is not grouping like it used too in fact at times it's doing something like 10/15mm if not more edge to edge at 25 yards!
I suspected the barrel sleeve so removed it, it appears it can be tweaked a little and I read pulling it half a millimetre away from the action can cure the grouping problem but having had a good look at it I'm thinking it might be a better option to go with a fresh sleeve totally floating barrel.
Incidentally I tested it without the sleeve totally floating and it was punching one hole again