Andrew,
Were the wipers working, then stopped? If so, it may well be the park switch, which is part of the wiper motor. These are cheap and easy to replace.
I had similar problems on my +2, but it was down to previous owner "modifications": no park switch; wrong type of switch on the dash, and incorrect wiring.
The first thing to do is to figure how it is supposed to work, then get out the volt meter!
The wiring should be very similar to this:
http://www.mgb-stuff.org.uk/s_wiper.htm
(look at "early two-speed")
good luck and best regards, iain