I would like the replacement unit not to be controlled by a PIR switch (which keeps turning the light off!) but by an external weatherproof switch. Ideally the light switch would be reachable from the ground, but I suppose a cord-pull would do the trick. I do not really want to add an additional weather-proof switch to the external wall.
The origin of the supply is the fused upstairs lighting ring main located in the loft.
Nothing fancy needed - or solar powered!
Is there such a device on the market?