Now then, a year ago I would have taken it down to the garage to change the bulbs. At the weekend however, I thought it through:
"Can't be the bulbs, 'cos both of them have gone at once. Can't be the fuse, 'cos everything else is working. Must be something else....but what?" I then remembered a loose 2-pin contact I had seen earlier under the bonnet while checking levels. Quick flip through the Russek, cross-referenced with the Haynes BoL and I discovered there is such a thing as a "reversing light switch" on the gearbox.
Smugly re-connected contacts
Anyway, my point is that this forum and the advice of the people on it have given me the ability to think the problem through, form a hypothesis, check it and get a result. I'm really quite chuffed with myself, coming from zero car background as I do....
Thanks lads
Oscar