Si, my apologies, my brain was nowhere near in gear. I was picturing the MAP sensor, not the FPR, which obviously, as you say cannot be "unplugged"!
It may be true that OP cannot get it out then put it back in with the existing gasket, but Island 4x4 sell them (Britpart ERR6761) for 25p each. So OP could take it out, check it clean it then put it back in with this O ring.

Hope this info makes up for my stupidity!

No probs. The issue with the gasket is not cost or availability, but working out which one you need in advance.

Still intrigued by the fact that stopping, removing key then restarting clears the problem, albeit temporarily. I therefore can't help but think that the ECU must be aware of the fault, else how else can a restart reset it? As I said earlier, that definitely happens when the wastegate thingy is playing up. But when it happened to me I had no frightening stutter, just a patch of gutlessness. As OP has Hawkeye, I would have thought that a fault should be showing on it. But I really am a beginner with ECUs.