Thanks for this. I’ve made a small amount of progress since my initial post. The haynes manual I was given with the loom and I’ve been using for the diagrams is the owners workshop manual (purple cover). I found a second manual yesterday, the service and repair manual (red cover), managed to find a pdf version online and the diagrams in it show both the diode wiring on the ABS circuit and the 3 pin fuel sender wiring. As you correctly identified the brown/red goes to a fuel computer, however I don’t think the car this looms from has that as theres several other cables going to the fuel computer which aren’t on the loom.

they also show the brown/black core going back to the instrument cluster as did the other diagrams so looks like I’ve maybe got a broken core there, which I’m surprised at as all the other cores within the main loom have belled out ok with a meter.

i still can’t identify the red/blue core though. These new diagrams show the glovebox light as being grey/black so I don’t think it’s that. Given the csa of the core I’d be surprised if it was just for powering a lamp. From memory I’ve already got the glovebox light marked as another core, will check later. Think I may have to split the loom and eyeball it to see where it goes.

finally, don’t suppose anyone has a copy ot the red haynes manual they’d be able to send a copy of page 245 please? It’s the diagram that shows the wiring for the radio and also shows the key for fuse sizes and core colours etc. for some reason this page is blurry (and prints blurry) on the pdf version I found online.

thanks again.