OK, so I asked the others and suggestions have been -
The Railway Inn, Forden, google say they do food
Montgomery lots of eating places, only 5 minutes drive away
Coed y Dinas, Welshpool but they've got a winter fair so probably really busy
Bring your own sandwiches so you can chat and look around for longer.
I've also sent an email around to make sure all the cake ingredients are listed.
hope that helps.