4. I'm surprised at the price of some heated towel rails and baths,
where's a good place to buy? It's hard to tell whether such things are
better/cheaper in France, has anyone any experience?

Dunno about France, but I got my bath from City Plumbing (pretty reasonable
for a corner bath), and my towel rail from screwfix (about 85 quid) - really
pleased with both.

Andy