Goods made to order - where do I stand?

Debated if this should be under Money or Law...

Situation is as follows - Back in Feb I ordered some goods from a small business that would be made to order. Three months down the line I have seen photos of said goods part assembled and have been promised that delivery will be "next week" almost every week since early April. I still don't have them though.

If this was a B2C transaction for off the shelf goods I'd know where I stood on this legally, and I'd have a good idea if it was B2B for off the shelf goods as well. However, because it's a custom order I don't know what rights I have to request a refund at this point, or if the best I can hope for is a partial refund and the goods & parts in whatever state they are currently in?

Does anyone know?

Julian