I'm indebted to regular contributor Walter for pointing me towards the Natural History Museum's Postcode Plants Database. The idea's simple. You just pop in the first part of your postcode et voila! All the native flora recorded in your area is listed!
So having entered CT11, I found an extensive list of everything from Annual Beard Grass (something you see a lot down the Belgian Bar), to Black Bog-rush (the morning after a night in the Belgian Bar). Yep, from Nipplewort to Rough Chervil, from Stinking Goosefoot to Man Orchid, it's all there. It even gives Latin names, lists everything under type (e.g annual, biennial, perennial, creeper etc), has photos of many of the plants, and recommends which would be suitable for the garden here at the old cliff top mansion.
Right! I'm off down the garden centre toute de suite to grab myself a Stinking Iris!
Postcode flora at Natural History Museum