Dave Plowman (News) used his keyboard to write :
It was well and truly fried. Only heatsink for the power Mosfets was the
thin ally case - and a small cooling fan. Not that much for a device
likely mounted inside a cupboard of some sort.

Rectifier was short circuit and a transformer burnt with half the
laminations lying loose inside the case, so gave up.

There is a UK after market replacement with a good reputation, at
around the same cost. My own PSU was mounted to draw cool air in via
the floor. I soon found the disadvantage with that, was that on the
road all sorts of muck would be ingested. It had a better heatsink than
you described, but the cooling fan had failed due to the muck it had
swallowed. New fan and move it to not draw air from the outside and it
has been fine since.