I'm not sure how effective winter washes are against the fungus which causes scab, though @Bijdezee may know better... The fungal spores can blow onto your tree from a considerable distance, and there aren't any fungicides licensed to kill it on edible crops in Britain. However, you can reduce it a bit by clearing up the dead apple leaves on which the spores over-winter. And the apples are still edible - you might want to peel them though.
Since 2019 I've lived in east Clare, in the west of Ireland.
I dont think there's actually a cure for scab but the winter Wash is said to help resistance to it.
I think correct pruning, keeping the centre open (should be able to throw your hat through it they say) will aid air flow. Picking up and disposing of leaves and cutting out affected branches.
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I may be wrong however, but at least my reply will bump up your query, and someone else may be able to advise further
I live in west central Scotland - not where that photo is...
I think correct pruning, keeping the centre open (should be able to throw your hat through it they say) will aid air flow. Picking up and disposing of leaves and cutting out affected branches.