TBH I will admit that this thread has made me think a bit about how much we spend / waste in the mogrim household - although there's no way I consider myself to be rich/elite (at least financially) I'm happy to admit that I'm not poor, and that a little more careful budgeting would probably be a good thing...
Still, and without publishing my own data, as an example of why I don't consider 40,000 to be that high a salary I've worked out roughly what living in a fairly average neighbourhood in the south would cost - where I've no idea what the figure is I've used TJ's numbers:
Mortgage: £1320 (Semi in Croydon, 30yrs @ 4.5%)
Council tax:£110
Utility bills: variable - maybe £120
Food: dunno - maybe £200 (seems optimistic, with a couple a kids anyway)
Transport costs: car 314 (from the car running costs thread - the OP's diesel Astra)
Clothes: 50 (I'm assuming a couple of growing kids here)
Insurances: £13pcm
Total = 2127pcm = 25524 pa
40,000 = 26800 after tax (aprox., assume 33% tax).
Giving a disposable income of just over a 100gbp/month. Certainly not poor, but hardly rich either.