Forgive me for being blunt, but pigs refusing fresh veg could quite possibly be overfed pigs - how much weaner ration are you giving them?
I'm not an expert, having reared just two OSBs, one to pork weight and the other to become a breeding sow, but in my limited experience, OSBs being medium-sized pigs, I found that just under a pound of cake per pig per month of age up to a maximum of just under 4lbs cake per pig per day was sufficient for free-range weaners with free access to plenty of straw, hay, grass, roots, etc and being given plenty of veg. They were hungry enough to be active and pleased to see you and beg for treats (bananas for Meg, apples for Gaby) but not ravenous - and didn't lay down too much fat.
The experts on here say you should calculate 4lbs fruit and veg to replace 1lb cake, so for more than a handful of fresh fruit and veg, the cake ration should be adjusted down accordingly.
At 7 weeks I'd have been feeding about one-and-a-half pounds of 22% weaner pellet per pig per day. I'd up those figures if the weather was cold, and if the pigs had no access to foraged food.
Meg is currently (fingers crossed) just in pig again, so has been on increased rations in the pre- and post-hogging few weeks. She's sleeping a lot, rarely out and about except at mealtimes. Next week her rations go back to normal, and we'll see a lot more of her out and about rootling in her paddock.