Is there a clutch microswitch overide fitted, most machines have them these days, it allows the microswithces to be overidden which will allow you to disengage or engage to get you out of trouble and back to the shop....
some mtors need a bit of coaxing as well they get a bit lazy as they get older...we just had a new clutch fitted to our 44 as the old one was rat@#$.....microswithcehs can be a problem also...they can get stuck with only a bit of dust and oil etc etc...i usually give them a spray with CRC eletrical cleaner seems to work pretty well.
As R405 said try the fuse first it would be the logical first step. also have a look at the clutch engaement switch on the panel they can be a bit dicky too....if your familiar with a multimeter this can help isolate a problem very quickly...just have a think a do some problem solving...usually works.......
then again sometimes the part is just F%^&#D and needs burning!!!!