What to do?

Oh dear, that poor dove does not look well, no expert but wonder if it's avian flu? Not much can be done I fear but you could contact here for expert advice ... helpwildlife.co.uk/.../

Thank you for your help.

You are very welcome, please let us know the outcome?

So I went out into the garden mid afternoon, and the bird had gone! Not under any bushes, not under the tree, not under the car. No feathers, no signs of an attack -just gone
I'm using my happy thoughts that it had an overnight rest. Stocked up on the fresh water and food I had left out for it, and then carried on its merry way.......

Well, good news of a sort, bet you wish you'd seen it fly away happily! Thanks for letting us know!