Last resort - check the fuel tank breather vent. The vent on my rally car got blocked and wouldn't allow more than a minute or so running before it just petered out. The vent pipe exited just above the back wheel and got blocked with mud and all sorts and caused a vacuum to develop in the tank. To test the theory, drive the car with the filler cap off so it can breathe.

Does it have fuel filter/mesh in the tank?

Turns out it was low on oil.

So the engine was seizing?
How low on oil was it?

It was very low. When the guy from the AA checked it, he said there NO oil on the dip stick. I had put 1/2 litre that week. It must have been very very low. Such a rookie error.

Oops! Hope no damage was caused :shocked:
It will be a good idea to change the oil and filter and check for any white metal.

That's a good shout.

I'm going to change the oil and filter this weekend.

There must be an oil leak somewhere. There's no oil on the garage floor, so how would it be losing oil?

Any smoke from the exhaust?
Any oil in the water?
Most likely rings and you are burning oil as you drive.

Piston rings? Sounds like a job too big for me