Spent a good few days cleaning out the rads, there was a considerable amount of coloured "gunk" sitting in the lower ones which took many many flushes with distilled vinegar, warm water, lots of shaking and reflushing until clean.
Replaced every o-ring on each fitting (except the internal rotary ones which are not serviceable) and each pump/res which has quite a few between the tops and needed custom sizes ordering.
Cleaned the blades on all the fans, pretty good really just a fine dust that got through the mesh filters, which I also gave a good wash.
Pressure tested each component individually and found that one 45deg double rotary wasn't holding pressure from one of the internal joints, even at 0.2 bar it would drop to nothing over a few minutes. It was probably fine until I removed it and twisted the rotary part, I guess the o-ring was stuck and has now torn. Really annoying as I can't seem to find a replacement anywhere, I have spare 90deg ones but really wanted an extra 45 for the inlet on the GPU block to get a nicer bend on the tube.
Here is how it sits at the moment, full loop pressure tested at 0.4 bar before filling with Mayhem XT-1 Nuke V2 Clear.
Don't plan on using any RGB but this is what it looks like turned on, plexi is a little marked up from years of cleaning, would be nice to have a tempered glass replacement one day.
And the reason I went for the acrylic gpu block is so I can inspect the fins without disassembling the block, and you don't really notice the acrylic with the lights off and normal viewing angle.
I may end up buying one of these
https://www.overclockers.co.uk/bitspower-45-degree-rotary-extension-fitting-black-wc-218-bp.html and using it on the inlet of the gpu.