Here's the only clue you need...
"I think the brakes may be ever so slightly binding on the front"

As already suggested by both Derek and chevrons2, if the brakes are binding to the extent that the LHM boils, which was why you lost all pressure, those calipers had not been reconditioned and should be sent back to the vendor for a full refund.

That supplier aka "The Abattoir"
caveat emptor x 5

Thought I'd fixed it... After a fast run today turns out not! No brakes again and VERY hot calipers ! The pads are literally just skimming the discs, however I dont have the shrouds on my car (yet) 2nd hand ones on the way.. do you think this is my problem?

Sorry guys didn't see the nice comments on page on the next page! He will be having them back, I have new ones on the way from ecas, quick question.. should I fit the shrouds before I fit the new calipers? I do t want to jeopardize them if the shrouds should always be used

"The abattoir" !

It's not the lack of cooling shrouds that is causing your problem, it's most likely those duff calipers.
The previous owner to me had removed the shrouds and I've never re-fitted them and have had no problems at all. I don't tow trailers and haven't yet descended Alpine passes(the Cambrian Mountains don't count!).
BTW, are the discs running true and in good condition?

Thanks for putting my mind at rest , yes the discs are true and in good condition all benit now have been VERY hot but not gone blue and not really binding that much but enough to cause the lhm to boil

I don't suppose this will be worth a punt, but check to make sure your master cylinder piston is retracting fully and allowing fluid from the reservoir to connect with the circuit. If there is something preventing the brake pedal from releasing the master cylinder piston to retract fully, then some latent pressure will remain in the circuit possibly causing pads to bind.

As I say, this is an unlikely scenario, but maybe worth checking.

That's a good shout and worth checking, will do that tomorrow thanks

Ok... So the new calipers arrived today from ecas and infoi a few hours late afternoon to install them the difference was already very noticeable so i took my wife and dog out in it for dinner as it's our anniversary this week and we happen to be child free tonight .. FIXED! a good 30 miles and some at 70 mph no big ding what so ever so Mr classic 2cv spares will be the recipient of how calipers back , goes to show buy cheap but twice and pay in the long run I almost just went for new calipers in the first place...I wish I had now! Thanks for all your reassurance and help here .

Is the dog called Lucky