My second seed order is with Real Seeds - http://www.realseeds.co.uk/ - a small business run by 3 people in Pembrokeshire.
There seeds are all open pollinated, so that you can save your own seeds in future years - they even send you instructions on how to do this out with the seeds. In short, I've been buying from them for a few years now, and have always found them extremely helpful and kind, and downright inspirational in their newsletters.
This year I ordered -
* Broccoli raab
* White cousa courgette
* Kailaan chinese broccoli (grown for fat stems not buds)
* Minidor yellow dwarf french bean
* Champion of England climbing pea
* Golden sweet mange-tout
* Morton's secret mix of lettuces
I'm looking forward to trying them all.