I stand corrected on the tag, and the frame welds look pretty good to my amateur eye, so my guess could well be wrong. Wouldn't be the first time and it probably isn't gonna be the last
There's not much to go by in the pics, but can anybody tell what the rear suspension looks like? Looks like an IRS unit with outboard brakes so not Jaguar based.
Also - have you measured the wheelbase? Is it more than 90 inches?
Edit - One more question: Is that roll bar attached through to the frame or does it bolt directly to the body?