Thanks Dave, since I posted I worked out how to remove the cover panel where it attaches to the windscreen so I could see the connecting rods etc. I used a drill to operate the mechanism and have managed to realign the forks and the pins so at least I can now attach the soft top. My second problem remains however that I cannot get any movement from the motors to resynchronise the mechanism. I've tried all the advice i can find about removing fuses, opening the boot, closing the boot, holding down the console switch etc but nothing seems to work. I guess there's either a microswitch that needs adjusting or there's a dead electrical item somewhere but I don't know how to go about testing it.
If anyone has suggestions please let me know.