Got some more work done this evening.
I decided to swap to the wiring loom so I can use the inertia starter and solenoid and also means I am not using a hacked up loom. Well that was the theory.
The starting point:

The practice was as follows:
1st I replaced the iffy red crimp that was used to extend the oil pressure sender line, this was a simple cut out the connector and solder in a new bit of wire (hopefully long enough else it's soldering in situ, which will be fun)
I then found the reason my wipers never worked properly on the car that donated the loom: some tit cut one of the lines. To fix this I cut out about 1.5" of wire and replaced it with a length cut from a rear loom as this won't be used.

Next I looked at one of the in line fuse holders that had been bodged out in favour of a blade fuse. I didn't do much initially bar cutting out the bodge.
While I was inspecting the rest of the loom disaster struck! It seems something had hit the bundle of wires near the alternator connector. After cutting away the loom tape the extent of the damage could be realised. There was only 1 cut wire (tacho feed from the coil), the rest amounted to the large +ve feed was a bit crushed with some damage to the outer and a few more damaged outers. A bit of electrical tape over all these should prevent any mishaps. And again 1" of wire was soldered in to fix the broken line. This all sorted I put 1 wrap on tape round to hold the bundle to endure the fix was ok. Once I am happy I will wrap it properly.
Before:

After. note the tape on most wires and the new section which has been shrink wrapped as have all new joins.

I finished up by replacing the fuse holder. Whilst digging in the big box of mini stuff to get the rear loom I cut bits from I found a section with a fuse holder in VGC. This was cut from the rear loom and then spliced back into replace the bodge for the blade fuse.
I am hoping I now have a serviceable loom and no more fixes will need to be done beyond replacing some blue crimp female spades once I order in some proper ones.
Also need to try prise the bullets out of the front to rear join, other wise I will just cut them off and use new spade connections.
Oh I also discovered there's a section of wire for the ignition where a safety switch would go on auto's to stop you starting the car in drive. I am tempted to use this to put in some form of basic immobiliser, but we will see as it's also 1 potential thing to go wrong.