Ignition load relay

[mark1968]

I have a 1982 V12 HE and the wipers, screen wash, horn and heater blowers have stopped working. I have read that this is usually caused by a faulty ignition load relay.I have checked the relay and it energises and has no resistance through the contacts. It also has 12V at the switching contact. All related fuses are new and intact. I did have everything working a couple of months ago, but now it has stopped again. I just need to get the electrics reliably working so that I can take it for it's first MOT in about 5 years.
Many thanks in advance.
Mark