OP said: "needs a new exhaust as cat is on way out"

Implies it's just the cat that needs replacing. I'd be tempted to get a cheap on off ebay and fit it for the MOT (it probably won't last long). I'd the knock the guts out of the old one and run on that all year, re-fitting the new one just for MOTs.

Other parts are presumably straight form the same era's Mondeo or other common Fords and are cheap as chips in either OEM or pattern form.

The Puma was based on the mid 90's Fiesta and was an excellent car, we had one for 6 years and during that time other than the normal (and expected) worn front suspension bushes and failed heater valve gave no troubles.

Problem is they are rotting away faster than most cars of their era especially around the rear wheel arches (this normally started just after the 6 year warranty expired) and in the sills and sometimes in the floor pan. I cannot honestly remember when I last saw one that did not have the rear arch rot.

Some mechanical parts are unique to the Puma (the 1700 engine was used in no other Ford) but most are not and are typically reasonable priced but body repairs can be very expensive due to normal labour rates.

Before you spend any money on get the body checked over to ensure it will pass an MOT, you don't want to go spending several hundred pounds sorting it mechanically to still have a pile of scrap on the drive.

Puma is destined to become a classic. A friend like hers so much that she has just had both front wings replaced. That cost more than my Merc for the same work. She has also had the rear wheel arches done. A little crazy, maybe. There is alot of sentimental value in that car because it belonged to her now deceased daughter.

That is understandable.

Collector-worthy or not, I would be tempted to put the Puma on eBay and see what you'll get. I know a few people who race them on track events and one like the OPs would be well received, as they'd do any work themselves and it doesn't need MOT etc.