Could be bacterial canker especially on your prunus. In spring-time, did the indentations ooze with a thick sticky substance? If so this would make the outcome certain.

It wasn't nearly as marked last spring so I didn't notice. I did see what looked like water but must have been sap running down the trunk from the lesions one day but that seems to have stopped. This poor damson has never been healthy - every year the leaves get attacked by something that eats holes in them. I posted pics here a few years ago but never found a definitive answer. In desperation last year I sprayed with a systemic in the evening and it helped in the first part of the year. Seven damsons set but none reached maturity. I think it will have to go.

Is the infection likely to remain in the soil?

Its in a fairly windy spot but mild,(only two light frosts so far this year) and I chose damson as being most likely of all the fruits to stand up to it.

Certainly looks like canker to me. Have a look at what the RHS has to say, it would explain the holes in the leaves too!

https://www.rhs.org.uk/advice/profile?PID=86

Not as certain as Moon Grower. All our Damsons (and we have a lot) have this kind of hole in the bark. They also have holes in the leaves (definitely insect damage) and all of them produce, sometimes prolifically. Only lost trees to wind and one bracket fungus in the last 20 years.
I would just keep a close eye on it and wait and see if the lesions begin to leak gum, before doing anything.
As to the lack of fruit, that is likely to be a cold induced problem. In late frost years our crop is very much reduced as the blossom is damaged. Also pollination is affected by strong winds. Gales blow the bees away!

Some fruit did set but it didn't develop properly. In 2014 OH and I got a small damson each. Last year seven set and we got none at all.The poor tree's rather a waste of space apart from the pretty spring flowers.
OK, one more season then and if it doesn't perform this year its for the chop. Can I replant in the same place if it ast yearis canker?

Well now, there has been some sap leaking from one of the lesions and the flowering is pathetic, so it looks as though its time to replace it with something else. What a waste of the past few years that was...