CR123 batteries really should not be difficult to find since they're still
quite widely used in digital cameras and the like. Not every corner shop
will stock them of course, but most larger supermarkets and places like
Boots, camera shops etc should have stocks. You do often need to look quite
carefully - there are just so many different types of battery available
nowadays and it's easy to miss one particular smaller type. Also they may
well be shelved with photographic batteries rather than general purpose
ones.

John Dann
www.weatherstations.co.uk