sorry, but what a dumb thing to say... and moving on...
ok there's obviously something happening out there then, because when we tried the main type of machine we saw out there of four of us trying severing different cards each, none worked. Like I say we did find one machine outside Paris that accepted UK cards, but it was a different type to all the others we saw.
ok so guys... of all those of you that didnt have a problem filling up at automated machine - whats different about your cards?
are they newly issued?
anything special about them?
the cards I tried where
Goldfish Mastercard issued early this year
and a
Lloyds Visa Debt/Delt Card issued early last year
both chip and pin
from the hunting around I did earlier I thought it was something to do with carte bleu - maybe not... but it would be great to understand what the problem is, it'll be easier than talking all my mates into buying GSA

and I dont think I can fit a GSA tank on a Duc Monster even if the owner let me
I think you were probably unlucky, nothing more.
There are various types of machine, ranging from card readers built into what would otherwise conventional filling pumps, to what I guess you would call 'service' hubs. With these 'service' hubs you often have to insert your card, hit the buttons and then go to the conventional pump to fill the petrol tank as usual.
Both systems use a conventional card reader. But the reader needs to have been converted. If it hasn't been done (there are still some out there) then it will not work with a UK card. Go back next year and it may well work.
If proof is needed that it is the card reader, not your cards, that is at fault, it's easy to establish.
Do your cards work everywhere else in France? At the motorway peage booths, in manned garages, in hotels, shops and ATM's? I would hazard a guess, yes. If yes, then it can only be that the card reader at the petrol station has not been updated.
If no, then you need to speak to your bank / card provider and get new cards.
===
Of course another possibility is that you were not using the machine correctly, failing to hit V for Validate, say. Some of the 'service' machines' instructions can be a bit confusing as they often have to deal with multiple pumps and multiple fuel types. Factor in dirty screens, worn buttons and it's easy to see why a stage in the transaction might get missed. Please do not think I am calling you thick. I have had the same problem myself. Patience and trial and error got me there in the end. But some just will not work, not even for the locals.
I will admit to getting very confused at one station with a 'service' hub machine. It worked fine and told me that I could take up to 120 euro of petrol, or somesuch huge figure. As there were several of us it was easier to fill up several bikes on the same transaction, not returning the gun to the holder each time. That was fine for my bike (30 euro on the dial) and the next bike (25 euro). Half way through bike three it all stopped, having only spent perhaps 85 euro out of the possible 120. Nothing would prompt the machine to restart, nor would my card work a second time.
The reason - when I stopped to read all the instructions - became clear. It was 120 euro OR three minutes, which ever came first. Filling my bike, filling the next bike and half of the third bike had run the clock down. It was a security function in the machine, I guess stopping people taking overly long fannying about, as indeed we had been.