The airbag light in my 95 XJR coming on and staying on?

most common reason is the clock spring behind the steering wheel, of course there are many other possibilities, then you can check resistance of every air bag (high resistance, open circuit) those are the easy checks. beyond that you start getting into tough things without having a code from the ecu to go by

The airbag has to be removed and the clockspring checked for continuity.

Hi as air bags are part of the body module circuitry they item can be fixed. it just takes some one with a bit more intelligence. as for warranty this old XJR must be well passed any warranty. the MOT however might be it's issue with a faulty air bag.

Find a Jaguar specialist. They are better than dealers on older cars.

I know a car a dealer failed to fix in a month. A specialist fixed it a couple of hours with no parts required.