Thanks for your advice, after discovering that my step buzzer was not working by bending my steps on a gate post, which cost me £300 to repair, it is worth looking carefully for the illusive fuse to ensue that the automatic retracting device is working. It was exactly as described on my sundance 630L, under a plastic cowl. Dont go looking amongst the fuses under the bolted fuse cover, it is to the left and above that box, you can only really see it if you squat right down and look from below. It was a 15 amp fuse blue in colour.
Anyway thanks for your help
Jonny Harris, May 2010