Hi mate,
Had a CRX VTI with the same roof as yours a couple of years ago, also ex Honda tecnician, actually went on the course for this model when it was new.
Problem is there are probually not many dealers who have trained staff to work on your roof. sounds to me like they are very unsure of the problem, the roof are a pain when they go wrong & been honest the first 1 I worked on was my own when it decided to jam 1 day
A possible cause would be the mechanism sticking due to lack of use, then stripping the gears in the control box when first used. Know you say your not hands on but can you operate the roof with the manual winding mechanism? Instructions in the manual, if so then I'd work it backwards & forwards a few times, lubricate all rubbers with silicone spray & go from there. Also can you hear any noises or see the roof mechanism moving at all when the switch is pressed?
There are several web owners clubs out there, appreciate yours is a UK car, but ave a look here at the Del Sol owners club http://www.delsolownersclub.co.uk/forum2/index.php need to register but they have a section devoted to trans top issues
Keep us posted