Apple tree disease

Can anyone please identify the disease on this apple tree we have inherited?

 

If it is just plain grey then it is lichen and does no harm to the tree. Good indicator of clean air.
If it is white like cotton wool then it is woolly aphid and needs to be got rid of with a soap based insecticide.
Scrape some off and look closely at it, you can find the aphid under the waxy wool like covering.

 

I agree with Palustris. Looks like lichen to me, which is well-nigh inevitable on any mature apple tree in a clean air environment.

 

Looks like its lichen then, someof the apples have black spots on them though, is this anything to be bothered about?

 

Could be scab, bad year for it round here with the warm damp weather. I spray with copper sulphate (Bordeaux mixture) every 2 weeks or so until harvesting. This is allowed under organic growing systems I believe. You can use Dithane if you do not mind sprays.