Hi Rach,
Thats a lot of dosh and a long wait for answers from CAB
There are plenty regulations in place like Distant selling , Trade Description, Sale of goods and Service consumer protection, etc
May I suggest you do a quick search of Trading Standards to help prepare the case.
Lots of easy to understand info out there but I don't commit it to memory just read it when something goes wrong, But an hour or two reading will help you clarify the case and could be time well spent, All the documentation will be great but you will still have a better chance when you know where you seller deviated.
Just a Thought