That makes me wonder if the previous owner ever really browsed this forum, the most obvious is that battery - wrong one for a Mk2 or 2.5. It needs a Panasonic 32 ah battery, that type fitted is more a Mk3 type. Just over £100 from a friendly dealer (with some discount) or our favorite supplier www.mx5parts.co.uk.
- I hear your ‘ouch’!
That boot rot comes from water ingress - can be from bunged up rear drains, but also from a rusty ‘rain rail’ (visible only with the top raised, it fastens the rear of the soft top to the cars body.) You need to pull up both side floor carpets and check for damp and/or rust, as in bad cases it can affect the ECU, which is in a compartment under the sloping section on the passengers side.
Most urgent, you need to check the front chassis legs - the two box sections that run each side of the wings.
These are an expensive touch as well (sorry about that) but do need replacing - check the forum. To check them properly, you need the car on a lift, with the engine plate removed - it protects the sump.
Overall, it’s beginning to look like a ‘walk away’ I’m afraid, but mine is in much better condition than that one is, and it’s an earlier car. Once a member, you learn all the tricks I’m afraid.
Afraid it’s becoming plain why the previous owner really sold the car, especially of he wanted to track it.
I’m feeling sick as a parrot just hearing all this stuff. I hope you didn’t pay a fortune for the car.