Solved the issues I hope.
Trev you were right it was a wire at the handle end so I simply (or not so simply as it turned out) re-wired the AC lead in which solved the problem of it cutting out on the different angles.
I had some interesting noises coming from the head/motor making me think for some reason brushes and bearings playing up. I found some up and down movement in the main spindle/shaft so I removed a small spring washer and packed an additional flat washer in there and sprayed a small amount of dry-lube on the shaft. This took the up and down movement out and appears to have stopped the noises but only time will tell.
Hunted around and found the original manual which came with the unit and shows I purchased it in 1994. Manual is good on unpacking and assembling the unit and use of it but that's about it. Happy to scan and upload it if anyone is interested.
I am kicking myself that I didn't take any photos during this process but was flying a little blind in doing this so....
Thanks to all who viewed this and Trev an Norm for the suggestions.
Cheers
Peter
Last edited by Peter D; 24/01/16 09:49 PM.