The Hawk T1 has a few years left in it but if and when it is replaced in the RAFAT depends on budgets, affordability, public perception, political will and commercial sponsorship. BAe are apparently developing an austere version of the Hawk T2 as an aerobatic jet for a couple of overseas customers, including (I think) India and possibly Saudi. It would be nice for everyone if BAe could do a favourable deal for the RAF on the back of that.
It would be very sad if the Reds ceased to be, but their cost effectiveness for UK PLC has to be justified and they should not be at the expense of an operational capability.