speeddial. I was not aware that England had an Air Force, in spite of certain efforts towards independence I believe Scotland, NI and Wales are still in there with us. I also think you will find it difficult to find too much evidence to support your view that the RAF, let alone the British military, will be provided with equipment by a generous government as soon as it proves a need, indeed just the opposite.
As far as the case for new Tanker/Transport aircraft is concerned, a quick perusal of many of the posts on these forums would seem to provide enough evidence from the operators and users for a long term reliable replacement, particularly in relation to the rapid deployment and out of theatre defence policy of the government. The policy requirement needs to be matched by the wherewithal to carry it out.