By contrast a 300 ml can of beer in Lidl was from 28 c and bottles of
wine started at 87 c

My Australian wallet just haemoraged at the thought! A slab (24 cans,
375ml each) is about $40 here or about $1.67 per 375ml can - that works
out to be @2.20 per 500ml. :-(

And yet, Australian's are famous/infamous for their love of the amber
liquid.

UK prices are all over the place with pub prices between £2 and £4 a pint .
depending what you drink and Where.
Supermarkets keep having price wars that sees them selling beer at below
cost, but even our local news agent will sell 1 pint cans (568ml) of Fosters
or Stella for £1 each.

To get it back on topic I think that the high airport price was simply to
stop people getting tanked up before they go on the plain, and unless you
are very rich or very stupid it works !!!!!