SWMBO & myself have both had our vaccinations.
Not being in the UK, I haven't had even one dose yet. My wife, who has asthma and is therefore at a higher risk, is hoping to get a vaccination sometime but not really expecting it before the summer. I'm not expecting one until maybe September. If we were in the UK we could expect it within the next 2 months.
I can't see any scientific basis for stretching that
I think that's not entirely accurate, the trials showed that considerable immunity for several months was conferred after one dose, and many other authorities (CDC etc.) have agreed that some spacing will not detract from the efficacy. There is some disagreement over the amount of spacing, true, but given the supply issues that some manufacturers are hitting, anything which keeps the vaccinations on track while those issues are resolved will help.
However they obviously realised that having more people wit limited immunity results in less pressure on the NHS
Well, less pressure on the NHS because fewer people are ill, which is surely good? Looking at it purely as a political game to play the NHS numbers is a bit unfair, those numbers aren't just targets, they mean something in terms of reduced deaths.
Inevitably there'll be a percentage of people who've had a single dose taking more risks over a longer period and consequently some of them will catch COVID whilst waiting for their second dose and a few will die.
Equally some people who wouldn't have been vaccinated would die without it, it's a question of probabilities, and the scientific opinion is coming round to accept some additional spacing, up to 42 days.
That will have a perfectly foreseeable political impact but I doubt BoJo & Hancock will have looked that far ahead.
They're politicians, everything they do is based on possible future political impact, at least up to the point where they don't expect to be around to handle it.
I can't imagine that this is anything more than political expediency over scientific advice.
Political expediency in what way? Are you suggesting that possibly saving more lives is being done just for expediency? That's reaching a bit, and scientific advice is not against this. This whole situation is new, and the scientists are no more expert than anyone, yet. They are naturally (over)cautious, and government has to look at the big picture & do what it thinks is best on the whole.