So after getting the waterpump sorted, I went for my WOF (like an MOT for you UK lads). Failed on two items, one being the plastic surround on the drivers belt buckle (the part to connect into) had split, so a bit of plastic glue sorted that out.
The other item was a bit more fun to resolve, turns out the side repeaters were not orange during operation (no pun intended).
Now the bulbs used on them are white, and while I could see some ones for sale on Ebay which had orange bulbs, I couldn't see anything to be had locally.
Referring to the image below, you'll note that between the bulb and the external repeater lens is another lens, this one is orange (or is meant to be), to make up for the lack of orange bulb.
Now it seems that 31 years have taken it their toll on the poor things, they were very faded, so in true Baldrick fashion, a cunning plan was hatched.....I would paint the faded lenses.
Now of course using 'normal' orange paint wouldn't be much use, but a bottle of Tamiya X-26 clear orange paint did the trick nicely.
Here's a photo of the a painted lenses vs a faded one.
Retest done the next week and WOF issued, so that's taken care of for the next 6 months.
Thought I'd share in case it is of use to anyone else.