Aha, I see. So basically, it would be even easier (and identical) if I took the caps off one of the boards, and just left the first board in place, then take the DC lines out the good board, into the caps, and from there onto the board? (Presumably the ground is still needing to be joined between the two caps on both sides, or rather that point becomes my ground on the caps-only side, and I join it to the ground on the board side?)
OK, so basically, your suggestion for best design can be simpified further to: single/pair of rectifiers to get our DC, then wires can be of arbitrary length as long as we have a pair of caps just before the boards...
Now, as for my predator boards, I seem to have damaged both of them unfortunately. It's not clear whether I will have damaged the amp modules either though (since I foolishly had them wired up when I first tested the PS... Learned a lesson there huh!)
Testing the predator boards, shows a circuit to ground from any of the AC inputs. I suspect that all the rectifiers are blown...? Would the small caps, etc also likely to be damaged?
Thanks Lars
Edit: With regards to builders notes as suggested by the previous poster. This silly mistake really comes from trying to implement dual mono power supplies without having understood the issues of a dual rail power supply. Perhaps it might be worth adding a quick note to the effect of "Stop, look, think" to try and help any one else avoid doing what I did...?