what to do with very large runner beans

If drying them leave them in the pods or you might damage them getting them out. They're not like broad beans,but you can cook & eat them fresh.

Make wine.  It's my Mother in Law's favourite.

Cheers,   Tony.

All mine got a bit too stringy weeks ago so I left them till they got bulgy and then shelled them and used them fresh.  They are lovely, I just steam them for a few minutes. 
In fact they are so nice that next year I'm going to plant fewer runners and some kind of beans (Borlotti perhaps?)which I can use de-podded for the late season.

As above, wait until the pods are dry, then the beans just fall out!

I love boiling the beans, taking off the skin when they're cold, and making some sort of marinade for them, like garlic and mayo with olive oil...

Sounds a bit fiddly, but is scrumptious!

They sound good, to clarify, do you shell then boil or boil then shell?

If the pods are still fresh, we shell them and freeze the beans in small packets handy for soupmaking.

So do we.