sarahe, Try the Wakefield/Pontefract areas for Glendennings. There were 2-3 of them in the old West Riding Constabulary. A Tony Glendenning joined in 1961, following in his father's footsteps, so he will be in his sixties. WRC headquarters were in Wakefield, but I believe there was a Pontefract connection with the family.
Regards, pityackafromblyth