LED pixel boxes. Not retro, but something I've oft considered building myself!
Yep - something like this:
https://www.ebay.com/itm/5-Channel-L...75.c100623.m-1
2A per channel at 8-16V output should do the job for a pair of boxes maybe. Can also ditch the Bulgins and the heavy mains cables too. If I were looking at a conversion project I'd probably start here but as I suspect Wayne has already put a fair bit of time, effort and £££s into the existing conversions a handful of resistors is probably the cheapest fix.
For the dozen or so in the inifinity tunnel, standard incandesent 25w Harlequins just to drain the residual current
For the rest, these: https://www.lyco.co.uk/crompton-harl...yonet-cap.html