On 21/02/2020 23:46, Graham. wrote:

I am looking for recommendations for what I would describe as
illuminated dado rail.

I don't want any incident light from the front, just a wash of light
on the wall above and below the rail.

Conventional dado rail. Stand it off (say) 8-10 mm from the wall with a
bit of batten 16-20 mm narrower than the rail is high. This tape is 8 mm
wide

https://www.screwfix.com/p/bendable-...00mm-10w/959fx

Also TLC do aluminium extrusions for use with LED tape