Chuck Update
Spoke to Robert Sorby's today about the chuck to see what their technical department recommended and they say should the chuck stick, lock the spindle, open the jaws to 8mm lay the chuck key in the jaws (like John's steel bar picture) with the handle pointing towards you and give the handle a couple of sharp taps with a hammer. They do not recommend using any form of washer no mater how thin, but told me that a little copper anti slip grease could be used.
So anyone having a problem with a sticking Patriot chuck, this is what the manufactures recommend.
Thanks again for your help.
Ed