update.....
thanks guys
"grumpy" took your advice and spoke to a greenfield dealer back in December and he mentioned the pulley is screwed on as "scouse" mentioned but cautioned me to be very careful as they can be damaged with brute force due to age in situ.
So sent my wife and son to work(smaller hands) and went the pliers and bolt cutters and screwdriver way that was mentioned and over a few attempts and sleeps it finally was clear of all wire scrap.
cheers
