Well it has got me stumped.
Opened the transmission up, and pulled every thing out and checked it and can't find a thing wrong with it, no broken bits - no siezed bits & only a few light shavings on the magnet, oil looked fine.
Remembering that there was a big bang and then it just stopped, it wouldn't go forward or reverse but the motor was running normally.
Just to be sure I went and started the motor to make sure the drive & cutter pulleys were working/spinning and they were fine.
When you hear a bang you expect to find broken bits but there is nothing and nothing to suggest that it may have jumped a cog or similar.
So is it possible that nothing broke but the cylinder block pump or the cylinder block motor have just given up the ghost and the bang was a last gasp.
ps: Neighbour called in so I did not get any photo's done yet but will when I put it back together.
Very confused
Rich