The new parts are printed in green PLA, so they stand out (and because it's what I had in the printer...)
So, here's the improvements to the original setup, the first is a predesigned part (slightly modified to suit my microswitches, but differences of fractions of mm off the original design, so not a redesign in my mind):-
Next up is another modification of someone elses design, given how much this is changed, it's almost a redesign, but only "technically", this is so close in looks to the original that calling it a redesign seems silly. This is the fan bracket for the extruder, I've modified it so the fan can be mounted with longer screws, and the fan blows more directly onto the nozzle, as the designer of the nozzle suggests. :-
Lastly is how the bed mounts now. Because I cut out multiple frames, I had a "spare" y-carriage, and realised, it has perfect mounting holes and everything to hold the cork/heater/glass sandwhich level, and still provide me with places to attach the bolts for the lower plate. You can clearly see the tape used to hold the sandwhich to the plate, I intend to swap those out for clips in the near future, but I'm happy with this levelling system also. I tried a three-point array, but found that the rear of the plate was raised in comparison to the front on the single-pin side, and I couldn't adjust that level out, so I went to the four-point system I'm used to. It's harder to level, yes, but once it's level, due to the nyloc nuts holding the bolts in place it won't move enough to matter.
Lastly, vanity shot, the printer in action with the new arrangement (printing another z endstop holder as I'm still not happy with how the microswitch fits, it's a very tight tolerance part there.