I'm lost here. You pay £1500 for a bass and they don't deliver what was ordered. No brainer, full refund and start the thrill of the chase all over again. Seeing as you have a few basses already I'd go for the £1500 all inclusive holiday. As an analogy, if your GF was in A&E yesterday and come out with bits loose and falling off, you'd take her back there to get fixed.
(The analogy dies when you ask for a full refund though!)