Hi Steve @sjbbeb
Sorry no one has replied to your message sooner.
I came across this problem with my convertible last year when getting it out of storage (it had got condensation damp) and everything was very stiff. I sprayed every visible hinge/joint with WD40 and down into as much of the concealed mechanism as I could – then spent a happy time raising and lowering the roof, initially with hand assistance, until everything loosened up (kept the engine running as guessed I’d soon flatten the battery).
Hope that helps,