David,
I would most humbley agree that anyone unfortunate enough to have a gun sleeved by Westley in the '60's did indeed inherit a dumbell.
No-one at that time really understood the job apart from Christian Ashthorpe, but once he had got it going they all wanted to have a go. Gough Thomas shows the Westley process in one of his books and you can see from the photograph that you are witnessing a piece of agricultural bodging. Thankfully times have moved on for the better in engineering and there are now many fine 'sleevers'.