I've been looking at some CAA rules in "Operation of ‘Permit-to-Fly’ ex-military
aircraft on the UK register"
http://bit.ly/2lK5zmK. It looks like complex aircraft are not ruled out. From page 16:
Many ex-military aircraft have specialised technical equipment or systems particular either to the role of the aircraft or the conditions under which it was designed to operate, or both. From design considerations for intermediate and complex types, the CAA will grant a Permit-to-Fly on the basis of a reasonable military service accident record (discounting military
action and high-risk training). To maintain or better this record under civil control, it is expected that the aircraft will be operated as far as possible to the standards used in military service
So theoretically, if you threw enough money at an outfit such as hunterteam.com to set up a maintenance facility, it still seems doable.