Honestly, there’s a question as to whether Heath is even an MP. Bexley was not exactly a safe seat and he came close to being ousted by Labour in ‘64 (roughly 4000 votes in it) and ‘66 (roughly 2000 votes in it). Depending on the size of the majority and the swing to get there, Labour might well have taken him out before the next leadership election.
Even if he survives, his majority would probably be tiny and he’d likely be a big target with a high risk of being Balfoured. That makes him somewhat less attractive than OTL.