Saving seeds from climbing French beans

These are the instructions for specifically saving bean seeds, but the principles are the same for many other varieties. As these instructions are to help people who want to preserve an old variety of bean (rather than produce a new cross) they suggest ways to keep the variety intact and unchanged. (From the Heritage Seed Library)

French beans self-pollinate and you can save seed from just a few plants; more is better and we recommend around 20. Do not grow two varieties side-by-side if you intend to save seed, or save seeds from plants that produce pods or foliage that differs from the majority of your crop. Dry the pods on the plants; if bad weather threatens pull up the whole plant and hang upside down somewhere warm until the pods are crisp. Once the seeds have been removed from the pods, ensure they are completely dry, place in paper bags or airtight jars and store somewhere cool. They should remain viable for up to three years

I had 3 attempts at Mr Fearns.  I let the pods go swollen but couldn't pull up whole plants because they were tangled in bean netting. I got as much stem & foliage as I could.  First try I hung them up in the greenhouse but the beans went mouldy in the pods.  Second lot I took indoors but the beans went wrinkly.  The third lot I left on staging in a shed but they also went mouldy but I had taken those pods off very late when I was clearing the bed so they were pretty soggy to start with.  I think my main problem with trying to save peas &  beans is wet weather. I manage to do small seeds ok.

This is an interesting topic. I have also had trouble drying beans (for storage, rather than seed, but the principle is the same). And I live in supposedly one of the driest parts of the country. But still they don't always dry naturally before the weather turns. Trying to dry runner beans, and borlotti indoors made them go brown and unappealing. I did wonder about hanging the whole plant upside down in the shed, but they are a bit unwieldy !

I think the secret of my success is that I forget to pick the beans early in the season (or don't see them), so right from when they first flower and form beans there are some which I'm 'saving for seed' (in other words I've let them go tough and useless for eating!!)

Back to the seed saving thread - I going to try & save some Mr Fearn's beans and Tutankhamun peas for next year but have never yet succeeded because of wet weather but I will try.
However, my polytunnel will be in use before the end of this year (I'm ordering it today - hooray) so I was thinking that next year I will plant a few of each (a bit presumptuous but I'm hoping here that Dandelion will put some in the seed swap again) in a corner of the polytunnel specifically for seed saving. Does that plan have any flaws?

I have plenty left of both from last season, and hope to save some more this year, so remind me again and I'll let you have some.