Isolating runner beans for seed saving

[Scarlet]

I've got two varieties of runner beans this year. Just a dozen of a variety that I would like to save seed from. Any ideas on how to isolate the dozen so they don't cross?

[muddled]

Do you grow on an allotment or at home?

I would grow one or two plants in a pot in someone's garden. You only need a few hundred feet distance at most. The realseed site has advice for beans....they say that if you grow different coloured varieties and chuck any beans that look the wrong colour once dried, you'll be fine.
I think the seed saving advice is at the bottom of their bean page (obvious now I've written it... )

[Scarlet]

I thought it was half a mile...I'll go and read up!

[muddled]

Aah! sorry.
I'm a donut!

The seed saving advice I'd read was, in fact, on their French bean page!
For runners it says "runners cross easily....grow only one variety if you want to save seed"

Apologies Scarlet....next time I'll check before posting

[Bigmallly]

The only thing I can think of is to grow them in tunnels so basically you need 1 person who is prepared to grow 6 of the same variety for you & you grow the other 6 in a tunnel, assuming they are not growing any themselves................still no guarantees though.

[Guest]

How much seed were you after? Is it worth isolating several flowers with the organza party/ wedding favour bags like sparrow uses for courgettes then marking. (I think it is mentioned on the 2015 seed circle thread)

[Jungle Jane]

Cover the whole plant with a cloche to keep insects out & hand pollinate? You could stop the plant when it's quite short?