It's unlikely for most of them - they were called "the Wets" for a reason. I guess some might split, probably no big names, but only if Thatcher looked like she might harm the party's chances. The SDP didn't just think Labour had lost its way, they thought it couldn't win elections anymore. Thatcher needs to be less popular.
Off the top of my head, a POD where the Falklands War doesn't happen; Thatcher still wins her second election but without the Falklands boost, with more discontent with her policies, and the SDP making a lot of noise. If Thatcher 'stays the course' anyway and they don't think she can be deposed, some 'Wets' might create a new party.
The problem is I'm not sure if it will last long enough to merge with the Liberals. If Thatcher wins in 1987, the Provisional Tories are going to look like chumps. If Thatcher loses in 1987 to either Labour or a grumpy Labour-SDP coalition, the Continuation Tories are going to cop the blame.