Can anybody help me please.
I'm usually very good at diagnosing problems with machinary but I need
help this time.
The above washing machine starts off fine on the program clock but when
it gets to program position 4 the clock speeds up and cycles quickly
through the other program positions in about a minute. I've never seen
anything like this before and would be grateful if any more experienced
service engineers could point me in the right direction.

When it has finished cycling, switch it of and allow it to stand for 1
minute. Then restart.
HTH