Is there a fig orchard I can visit somewhere near London? Or any flower market that sells fig plants? Columbia Road market has them?

Or local markets that sell fresh figs.

This might help

http://www.j-sainsbury.co.uk/media/latest-stories/2013/20130816-the-only-way-is-british-with-essex-grown-figs/

Edit :Sorry just re read your post, your looking for trees.

not sure how far this places is, but they have some good stuff per their web site.

http://www.readsnursery.co.uk/categories/Fig-Trees/

Luke - yes, I guess probably supermarts like Saisbury and Tesco might have fresh fruits for sale.  Would check them out for sure.  My preference is to visit an orchard or grower and see the plants with fruits on them.  If they offer a pick-your-own, that would be great then.

Bullet - the link you gave had me drooling non-stop.  Too bad, the RdB seems to be out of stock for now.  They have Rouge dB though and a few interesting ones like the Grise de Tarrascon. Hmm.....