Hi!
By the time I'd finalised the design for my friend's Z80 boards, JLC were doing a very good value C.N.Y. offer on these designs which worked out at approximately £2.65 per PCB as–delivered price, so I sent the Gerbers away to 'em, but a speaker protection module project from "Electronics Australia" has attracted my interest again, so I'll be looking at this problem afresh later in the year!
Chris Williams