Thanks for all the replies.
Finally settled on a B&B Hotel just round the corner from the bus drop-off. Not that cheap, especially at 1.02 to the pound, but worth it for a shower, breakfast, and maybe a small sleep. Plus there's a 50% chance of rain and strong wind gusts, so don't want to dawdle outside too much as only 50km to do by 3 p.m.
The F1 hotels are a great invention for the continent. Not quite so good for the incontinent though
Anyway, the nearest F1 turns out to be oe the wrong side of Valence, which I am determined not to venture into.
The Ibis Sud looks attractive but a bit more pricey, and not so close to the bus. An interesting StreetView timing effect: circumnavigate the hotel and most of the time you see a smart hotel; round one more corner and the hotel disappears and is replaced by a bare field. Satellite view shows the hotel still under construction.
A similar anomaly in later routing when Google Maps is determined to send me down a railway line. Almost all the StreetView and satellite views definitely show rails and sleepers. There is just on image at the end of the line which shows a shiny new cycle path, but I don't have any faith that they have carted away all the rails and laid 30km of tarmac. To be continued....
Bryn