The Hawk idea mentioned by Finnpog is probably the most sensible of the various concepts. With a bit of spending now, funding from the Typhoon T3 lines, you could probably buy 2 or 3 Hawk 200s for the price of one Typhoon.
It should be able to fulfil most if not all of the requirements for CAS, probably recce too if there was a simultaneous purchase of gen 3 RAPTOR which is much smaller than the version we currently ues. And as it's multirole, there's no reason why we couldn't go back to the mixed fleet concept of arming Hawks / Typhoons for UK air defence.
Hey presto - satisfy the requirements for Afghanistan, UK, and potentiall trg all in one platform. It'll never catch on!