The Lucas Fuel Reserve valve is good bit of kit, really useful, however it suffers from a few problems.

1) The wiring insulation on the switch is of the earlier rubber type like UK household insulation from the 1950s, this, over the years, always falls to pieces with the result that it burns the wiring looms out in all Feltham cars.

2) If the pipes crack (they are made of brass) there is a real chance that the engine may be damaged - we had a DB2/4 MkI in the summer of 2012 with just this damage.

3) The filter in the reserve valve pipes are not great and a supplementary filter should be added, the one fitted near the carbs on a DB5 to DBS isn't great  either, use a  Glass Bowl fuel filter with our specially made adaptors.