Anyone recommend a good motion sensor
Ideally running on normal batteries (eg AA)
Temp and humidity bonus
"Good" is a bit subjective without any context. What (if any) have you tried? What are you looking for? Speed? Accuracy? Size? Detection range?
I like Hue myself, both indoor and outdoor react very quickly to motion in my experience with no false alarms, but the detection range isn't that big. Temperature and LUX as a bonus. Runs on AAA batteries.
I also have Iris V3 IL07, but they're imported from the US so might not fulfill the "UK" part of your request .... I find the detection range on those to be huge, but not quite as fast as the Hue. They have temperature and humidity too. These run on CR123A batteries.
If you want small and discrete size then you could look at NYCE. You'll also have to import those from the US though. They're pretty quick to react, have temperature and humidity and do two form factors - wall and ceiling mount.
And of course there's also Xiaomi Aqara and variants, much cheaper but can be somewhat challenging to keep them connected to Hubitat as they're not quite ZigBee compliant.
all mine are z-wave, but I've had nothing but issues with z-wave so making my office at then end of garden zigbee, id forgotten about hue, but was looking for what people were using in UK which runs on standard batteries, if there were any bargains from ali etc which were OK and ran off standard batteries
Although this was true, since @markus has released his excellent drivers for these devices, they are much more reliable.
As with most zigbee devices though, a good mesh is needed.
While they don't work off AA batteries (they use cr2450 so still cheap and easy to get) look at the sonoff ZigBee sensors. Markus has drivers for them and you could pick up a couple for the same price as the Hue sensors.
do the sonf report lux?
Not zigbee, but I find that using a nodemcu with konnected software with real 12v honeywell pir's to be far better than my old Samsung battery sensors. And comparable in price.
If you can find any AlertMe Motion Sensors on eBay, I've found them to be small and reliable. No lux, just motion and supported by my driver (with presence monitoring) or the Iris V1 system driver.
Got my last few for £2.50 a pop. 
