A week off swimming and only a little exercise altogether seems to have help my elbow. I have been doing wrist pronation and supination exercises everyday although not as often as advised.
On waking this morning my elbow ached less than it has for a month and so I went for a short swim. I focussed on careful high elbow technique but not to the extreme nor with overt should extension. I tried to keep my forearms relaxed and included bilateral breathing lengths to reduce the asymmetry of the session. The pace was modest but acceptable.
Now the elbow feels pretty good although I'm aware it's not 100%. Let's see how it fares tomorrow - I must do the wrist exercises later this afternoon.