WEBF,
You need to recalculate - as currently planned, the last SHARs will leave service in 2006, so it's not a ten year period. It's actually a six-year period. And if reports of Uncle Gordon's miscalculations with the finances of the nation are to be believed, the MoD will soon be regarding even £36m p.a as a significant chunk of the defence budget.
Additionally, you might be interested to know that your complaint that the RN will lose skills in the air-air role is being addressed; the FAA (or so it's reported) will be looking to put pilots in F3s or Typhoons and increase the number of exchange slots with the USMC (presumably F/A-18 unless/until the AV-8B+ gets AMRAAM).
JN/Nozzles
Who lays down the ground rules for who is the DA and how long their A over the D lasts? I assume that it's buried somewhere in the original contract? If the customer can say when an airframe is mature and can then set about giving it a Jag 96/97 style update, I wonder why the GR7 and GR 4 weren't declared as mature ages ago (particularly the Tornado)?