All the plumbing fittings I buy in France in the local discount sheds are BSP thread - I believe that's one of the few British sizes that were endorsed when stuff was harmonised years ago. Some of the fittings even have 1/2 or 3/4 stamped/embossed on them.1/4" Female BSP thread is 11.92mm (0.47"). It's parallel. 19TPI
Maybe a bit of a surprise, but a few Europeans do use BSP.
I tend to agree with RWD3M in that the male fitting is probably something else, maybe metric?
Ok, an end to the union thread type, it has turned out to be metric fine, so I thought no chance of finding the corresponding female portion, but as it turned out while I was searching in Bakers Bits in Exeter in walked a mate of mine who used to look after all of our welders at Plus while I was there, anyway after a root around a box of odd fittings in the back of his van he came up trumps, so new hose and crimps and jobs a goodun, many thanks for all your suggestions guys, you're all stars
This might me one for @Joe Irvin
He’s a GYS technical bloke...
Edit:
Scratch that - didn’t notice you’d already sussed it!
Yeah, the bizarre thing was the 1/4 bsp female fitting that was on there and didn't look like it had been added at all, bizarre