Seems like we're all right.
After lunch we thought that perhaps the english help line might just put any old answer machine message on to make people go away. And hey presto they were there after all!
This lady still saying we need an S1 but also bank details, translated birth certificate, proof of income, as well as proof of residence, and passport.
In my wanderings around the internet I came across something that said there was an overseas health team at the DWP (DHSS as was). Let's try them.
Oh yes, says the lady, what you need is a letter from us saying you were part of the english health system which has limited period cover in france and will get a state pension. Not an S1. Where would you like it posted to?
Apart from the fact that it might take 2 weeks to get here which will give us time to get the birth certificate translated (how many words are there on a birth certificate?) everything is hunky dory.
Look forward to the second half.