Get in touch with Trading Standards. They will be more informed than Citizens Advice. I believe where the item is faulty, you are within your rights to have a full refund. If you paid with your credit card (even if only a deposit which is more than £100) then you can legally make a claim through the card issuer.
Always write letters, keep copies and send by recorded delivery. Keep a diary of relevant dates. Link below may be useful.
http://whatconsumer.c...he-sale-of-goods-act/