I understand the sentimentality - there are times I wish I still had my first car too.
But that one was owned by my dad, when he bought it brand-new, so I knew the driver, and every mile covered & penny spent on it.
The way I see it (objectively), is; you can end-up spending circa £1300 (estimated, but at least) and have a 15 year old car, which you hope has no more issues to throw at you / let you down with.
For (a good bit) less money, which can go towards insurance, or a service - (even a set of bigger wheels) - you end-up with a ten year old car with a more powerful engine, no rust, warranty and the big jobs done.
Something I have, (which that £300 saving could easily pay for), is AA breakdown cover home/roadside & relay, plus
breakdown repair cover, which acts like an ongoing warranty, except there is no limit on age or mileage. I've used it a few times, and it's well-worth the cost.
Project cars can give a load of satisfaction, but only if;
- you have the skills not to have to pay others to do the repairs
- you have the tools you need
- you have the time to devote to dismantling, repairing & rebuilding the car
If you don't, they become an unreliable, money-pit and a real PITA that you will grow to resent.
You have to take a step-backwards and be objective & honest about yourself, the car, what you want out of it, and the finances you are willing to deploy to fund whatever you decide.
Best wishes whichever way you go.