I agree it's hard to judge the height of an aircraft by eye. However, if you live by an airfield and you know what an aircraft looks like at, say, 1000 feet, then you can tell if one is substantially lower. Also, you can get a rough figure by timing the aircraft through a particular angle. Or maybe K Lacey has a rangefinder.
However, I don't think it's for us to say that she should like aircraft and not whinge.
We have a right to fly planes and she has a right not to like it.
And we have a duty of common courtesy to minimise noise. I'm sure most pilots flying into Redlands respect that duty. If K Lacey thinks some pilots are not following procedures then, as pointed out, PPRUNE is not the best place to solve the problem but rather to take it up with Redlands in the first instance.