An update for you:
The back isn't removeable on this model, just a circular plate for access to the belt and little else I'm afraid. Unless I'm missing a point, it looks like a major dismantling job to access or remove the plastic chamber - it's as if the whole washer was assembled then the case wrapped around it.
Anyways, I removed the fan on the top to at least have a look, and there was a web of hair and fibres partially blocking the chamber.
So cleaned out and far as I could, and retried with fingers crossed... it only ran on intensive dry for a few minutes again, so no change there.
Thinks... if there was an obstruction at the top, then there's likely to be one at the bottom elbow that feeds into the drum. So fan off again, and using a wire/hook I managed to blindly drag out another clump of hair and fibre from the bottom of the chamber.
I tried running it again, and this time it lasted the 30 minute program time, for the first time in weeks.
I programmed it to run for 1 hour overnight, but discovered that it failed after 36 minutes when I checked this morning.
I've tried the 30 minute program again tonight, and it's back to failing after a few minutes again.
So... thoughts please?
I guess I need to get it fully cleaned out whatever, but what would be the best way to do so? I thought about blasting it with a pressure water jet to save the dismantling job.
Or do you think this is all a red herring and a control board fault is still more likely?