Hmmm
My understanding is its not hugely clear.
ANO 2009 Section 166 applies (167 cover how car you can fly near people).
First the rules change around controlled airspace, so this is about general airspace and anything over 7Kg but below 20Kg is limited to 400Ft by the ANO's.
The problem is its not so clear for anything up to 7kg. You might expect that they should inherit the same rules as the 7 to 20KG group and then add more in, but don't the ANO says the operator must maintain unaided visual contact (glassed are not classed a visual aid, it means binoculars or FPV goggles) which is what in effect limits distance you can fly, BUT they do not specifically state height or distance, unlike the 7 to 10KG group.
Now realistically I can see my Phantom to probably 500 ft up, on a clear day, however but anything above 250-300ft and I find it hard to know which way its pointing as the LEDs are not super bright, so for me, my flights tend to be up to 100m, and I have the Phantom limited to 120m height, and 500m distance. Ironically on an overcast day its easier to see the LEDs so you could fly further. Other people will have better eyesight than me, other may have painted their Phantom's black to see them better in a clear sky, but responsible fliers are not interested in breaking laws, we want to stay within them to enjoy our hobby.
I'm still not trying to defend the idiot minority who fly far out of visual range and cause risk to people or property, just noting the ANO's do not cover all cases.