There was a new Yorkshire Regiment dress booklet was handed round at my unit a couple of months ago, and it stated (with pictures) that the OG jumper with a stable belt could be worn. So i managed to get hold of one, and wore it with my C95 Shirt and stable belt for about a month until it started getting warmer.
I work at my unit a fair bit, and when I was on gate duties I preffered wearing it to my smock if i'm honest. Plus, I think it looks a lot smarter too.
We've been able to were our old style wooley pulleys over our 95s as long as they are ironed, ranked up correctly and the shirt underneath is also ironed. I think in some units the RSM can give the nod when it gets icers. It's not necessarily to do with the new barrack dress.