[Franek Grabowski]

Well, I am wondering that it could be actually a more complicated issue. Certainly, RAF as an independent force did not want to go under Army control again, but it somewhat did, forming TAFs. At the time, a new design was just impossible, but there is indeed a valid question about Vengeance.
Then, there is a question of responsibility, as if RAF leadership proven wrong, some of them certainly would have been sacked.
Another issue is of business-political nature - British manufacturers certainly were not that very fond of Lend-Lease, as it reduced placed orders for production. The fact is that several (not all) British designs were either out of concept or completely outdated and production stopped as alternative appeared. Many of minor manufacturers then turned for licence production, major overhauls and similar, not very profitable jobs. Appearance of a new US design both reduced production and was an excellent example of somewhat black PR - another excellent US type, that proves American production is better than British.
Then, there is another related question - which of British manufacturers was able to make a design and make a series of modern dive bombers back in 1930s? All major manufacturers were busy with their designs. Minor ones lacked technologies and production force (or whatever it is called). Having in mind this and all the above, how would you explain that to politicians?
As Ronald Reagan once said, politician is second oldest profession of the world, and actually not very different.