So ... is it possible for her to get through to T2 and the Escape Lounge? They charge £20 per visit and that would be fine. Would FlyBe play ball with this and get the OCS people to trundle her through? Do FlyBe need to know? She just tells them where to take her? Providing there is easy wheelchari access from T3 to T2?
Are you serious? No airline would play ball with this because you can only use the terminal that you are flying from. OCS would not be willing to take her to and from I'm afraid. T3 is actually the other end of teh airport to T3, but the point remains, you use the terminal you are flying from.