If you want more modern then something like the small Tannoy or
Quad products of the last few years but they may exceed your
budget. Older Gale (now I think a brand owned by Richer Sounds)
were also solid little units.
For the creme de la creme the BBC-designed LS3/5A which were made
by several manufacturers - Goodmans, Rogers, Chartwell, etc - but
you will be paying hundreds for them! (Probably the only speakers
you will buy secondhand that cost now more than they did new
15-20 years ago - they are that good.)
I have seen good ones go for over £1000 on ebay. But as said they are
superb

..
Whatever you do (a) get speakers that have rubber driver
surrounds - as against foam which rots - and (b) make sure those
surrounds are not cut. I saw a pair of reasonable TDL's yesterday
for £40 but one surround had a small cut in it and TDL are no
longer in business.
I have assumed in the above that you listen to a decent spread of
music types - pretty well none of the above will handle heavy
rock very well!
Apart from fleabay, look at what Richer Sounds have even new, and
also look at some of the specialist secondhand hi-fi outlets such
as Fanthorpe in Hull and Steve's Hi-Fi in Hastings both of which
have web sites.
And in the local papers .. sometimes the kids are clearing out the
deceased parents house and sometimes don't know what they are clearing
out as regards audio equipment;!..
--
Tony Sayer