If you have disconnected the element, and this has cured the tripping,
then it is 99.9% that the fault is in the element. On some Hotpoints,
the drum drops when the bearings are faulty (even if the bearings
sound OK, when the drum is rotated by hand), this causes the front of
the drum to cut into the element when the drum is loaded, so if you
remove the element, check that it has not got any nice new shiny
marks, that look like something has been rubbing on it, because if it
has, the bearings will need replacing as well.

Will do.
But I'm putting off removing the element for now cos it looks like the whole
drum has to be removed out of the case to do that.
I'll wait to see if the tripping has stopped and then attack it (unless I
can find my megga in the meantime).

Thanks Gavin - Kevin