T i m wrote

Coming down to the front and rear lobby lights off bade us realise how
dark it was out there but not just because is was close to sunrise (so
sunrise + N time wouldn't help) it was. So the next thing I'm going to
try is adding a 'rule' that turns those lights on when 'Overcast'.

Some like the Philips Hue movement sensor has a light level
detector so that is completely automatics. Just overcast and
not isnt enough, heavily overcast is very different light level
wise to medium overcast or light overcast.

It could mean they are on all day (and night)
but it will be interesting to find out.

I would also be interested to find a B22 LED Zigbee compatible
lamp to put in my neighbours (unused) outside light and trigger
it from the PIR I've ordered (with his full permission etc). ;-)

Should I be able to sum the rules, eg, Only if between sunset and
sunrise and the PIR is triggered, turn the light on for 10 mins?

You certainly can with the best of them.