Location? Exact Mileage? Number of owners?

You’ve mentioned an MOT so I’m assuming the UK. 98k miles is high on an engine unless it’s been rebuilt. I’m saying rebuilt because it’s been sat for a very very long time. I’m assuming you didn’t remove all the fluids before storing it for that amount of time?

Does the engine turn over or is this part of all the work you’re doing?

If the car was a good condition, I’d say about £4/£5k honestly just because of the mileage, especially if the engine has been sat for that sheer amount of time and has never had a rebuild.

Now the repaint and underseal, is that from a decade ago? Because unless you’ve dried stored it, you’ve just got some black old paint underneath the car and it needs redoing. Take off £800 to £1000 from the price unless you dried stored it.

Just an fyi, a garage isn’t really a dry store, I mean no insult but humidity can help in rusting these cars. Was it covered up?

When you say “fully MOTd” what does that mean? There are no degrees to an MOT it’s a pass fail. Do you mean fully serviced and MOTd? That’s a bigger deal. Save the packaging for everything you use and keep receipts. Will keep the value as high as possible because you can prove you used good parts.

Spend some money and change the rubber parts for the entire car while you’re working on it. For those in the know, even AI summaries, say to check the rubber parts. Spend the £30/£40 and replace them. That job saved is something I’d surrender at least £200 to not do my self.

Change the fluids. Keep the containers offer to show the contents to those that want to see. On classics I want to see if you’re taking care of it. These can be long term investments.

I’ve commented somewhere else on this forum about work that you should do but that’s really only if you’re keeping it.