Worth reseating, but suspect its BF'd
What does at duff code reader say the rev counter/speedo is reading - if that figure is correct, then that proves the panel is BF'd. If it also says 0, then the implication is signal not getting through (which may or may not be panel - I'd suggest swapping with your other to prove).
i haven't got that far. Will do shortly, but as its now working I doubt any faults will be evident. Thumping, pushing, squeezing the screen back into its socket had no had no effect.
I'm in two minds weather to just swap it out and be done (won't guartee a fix if it's speed signal) or leave it with the lappy in the car and plug in if it plays up again...?
If its happening regularly enough, I would personally try a proper reseat of the panel, followed by swapout if still reoccurring. That should help prove.
As its affecting rev counter, I'd say its more than just an intermittent speed signal. To check if speed signal is disappearing, goes Instant Cons on the BC misread? Does the satnav still track your location, and not stick at the location when the speedo stopped?