Assume nothing, is my philosophy, especially where Novas are concerned in terms of who repairs them. Many a bodge is easy to come by; many a fine Nova not so.
As for GM panels, there's a gentleman on Facebook called Anthony Drosos who is very helpful in sourcing many hard-to-find GM (as well as copy) panels if you're struggling to source them within the UK. Otherwise, just keep your neb close to what is for sale on this forum and you'll surely find what you're looking for, or find someone who knows how to get what you need.
If you're seriously struggling to source panels (copy or not), drop me a PM and I'll offer my help where I can.