If he can't get it fixed, I'll pursue it with Winchester.
If he can't, don't mention that anyone touched the thing when you talk to Winchester. They may void any warranty.
I am unfamiliar with the new M70 trigger mechanism but if it is like other over ride triggers, disassembling the mechanism and polishing the parts is not for the novice.
My guess is that you can jack up the trigger pull weight to the point you don't feel creep, but I would hate to use a 6 pound trigger on a M70.