Secondhand bookshops in the UK?

[Graeme Lyall]

There are quite a few books I would love to own - for example 
biographies of early botanists and plant collectors, histories 
of botanical illustration.  I feel sure there must be specialist 
booksellers in the secondhand/antiquarian trade who cater for 
this sort of thing.

Can anyone help with suggestions (in the UK if possible)?

regards


Graeme Lyall
uad1123 at dircon.co.uk