An update, we got there in the end, the 401 now has external LED bulbs all round including the headlights, I decided to use some new rear lights bought through BODA which had red lenses, therefore opted to put two stop tail bulb on each side and re locate the reversing lights.
Looking for suitable light units on line I found some LED bolt lamps at
Quicksilver Automotive Gil who runs the company was able to supply the lamps and wire to link to the existing reversing lamp switch, and also another kit with the same size lamps but red led's, wire and switch to fit fog lamps.
The lamps are very small but the light output is amazing, both reversing and fog lamps fit in the space adjacent to the number plate and are so neat and discreet that most people would not notice until you turn them on.
The lamps are small enough to be used as mounting bolts for the number plate hence the name.
Geoff.