I went in with the intention of buying a NAD C320BEE amp (£180) and a
pair of Mission M71i speakers (£60), but on the recommendation of the
salesman I ended up walking out with a Cambridge Audio Azur 540A (£180)
and a pair of Gale Gold Monitor MK2 speakers (£80).

Me? I'd get the NAD amp myself, though at this price range,
it's not the last receiver you'll ever buy. As for speakers,
I don't like either. I'd get as large a pair of bookshelf
speakers as I could find, or some used or demo towers.

For this sort of thing, and considering where you live,
I'd look at KEF and Tannoy, especially their older lines
from 1-4 years ago(Mercury - the old "M" line, not the MX)
are great sounding for the money. 100 pounds should get
you a decent small tower, in fact.