After quite a few hours searching online over the last few days, and a bit of minor fault diagnosis, I still have a none functioning convertible!
The red light on the rocker switch simply flashes constantly. When operated, nothing changes. No sound, or attempt at movement.
The majority of the fault diagnosis I have read has been for 'roof stuck down' - unfortunately there doesn't seem to be as much information for roof stuck up.
Thanks in advance, Stuart.