However, there are upwards of 100 Typhoons and 70 Tornados in storage, so the airframes are available...
The likelihood is that they'll re-equip with a variant of the Hawk 100 (T2), with BAeS providing the airframes and tech support on a lease as they do with the T2s at Valley. The 24 on the original lease are apparently specifically prohibited from doing formal aerobatics, to prevent the RAF from redeploying them to the Red Arrows. Anything other than the Hawk (given that the Typhoon would be too expensive!) would undermine the Reds' role as a demonstration of British aviation and engineering capabilities.