Ok, good, so then you agree that if the Tempest V hadn't been available, all of the 800 V-1's the Tempests shot down wouldn't have rained down over London.
Maybe the alternative approaches they would have devised would have shot down more than the 800 shot down by the Tempests, maybe less.
Now we seem to be rapidly shifting the goalposts, but anyway, I fully agree that 4x20mm is far superior to 4x.50, but OTOH for shooting down a non-maneuvering target that has a very limited capability to absorb damage even compared to a single-engine fighter, I'm not sure it's a particularly big issue.
Clearly the Meteor in mid 1944 was for all practical purposes a prototype. One reason I read somewhere for the meager success against the V-1's was that they had problems with the cannons jamming. Of course a serious problem for a combat aircraft, but nothing per se to do with the powerplant and no reason to believe it couldn't be fixed, as many other aircraft were very successfully using cannons by that time.
My point was that if all the effort they spent on the sleeve valves had been directed at jets instead, the Meteor might have been a much more formidable aircraft already by mid-1944. And of course, if the Tempest with the Sabre wouldn't exist, chances are the Typhoon wouldn't exist either, and Gloster would perhaps had more capacity for Meteor.