There's a Region 1 DVD of The Camomile Lawn for sale on eBay expiring March 30th.
It also appears that you can buy the Region 1 Camomile Lawn DVD directly from Acorn, the distributor. It's a fair bit more expensive than the eBay version though.
[edit: Frenchies, set your VCRs! The River King is on Canal Plus Décalé at 20:50 tonight, which is in like three hours. It'll be rebroadcast - dates later]