Interference capacitor has shorted .(It is attached to back of plate where mains cable supply enters) blows fuses with loud bang.
Question is How is the plastic plate (which clips in) removed without breaking it?

Geoff Ipswich, April 2011

Somehow you have to slide that plate about 8mm to the right, where the tabs meet up with gaps. I only managed this after breaking some of the end of the plate, but when I pushed it back in again it was easy to lock it in position with duct tape and some of the broken off plastic.

Phil, October 2019