OK - I have a diagram on how to wire it using a 5 point relay - is this correct ?
The idea will be they go on with the ignition and off with the sidelights - I've checked and the sidelights (position lights) stay on with the dipped and main beam. There is an ACC (accessory) wire in the underbonnet fusebox - Haynes manuals - thank you...
EDIT - ignore the connection between pin 30 and 87a - I copied this from a diagram...