Sorry, I don't know anything about posting out of the U.S. There might be some sort of laws/regulations with customs or USDA that I don't know about so I'd have to research it before agreeing to post to the U.K.
They practically grow themselves. About shipping internationally--I've read that small seeds such as flower seeds aren't a problem, but bean seeds might well be. They are prone to fungus. Know for a fact they can't be sent from the UK to the US. Don't know about the other way 'round.
An easy support for pole beans is taking a few bamboo tall stakes and weaving them through the top of a chain-link fence (assuming you have a chain-link fence) and pushing them into the dirt and then attaching twine in a diamond pattern between the top of the stakes.
I have had seeds get through to Australia for people at gaming sites. ***** customs. If someone asks when you post at a post office, tell them its some photos from a holiday :)