Mysterious beans

These turned up in the garden. Unfortunately, I have no idea what they are, whether they are edible or not. It is a climber with big broad leaves. The plant is robust and just one covered the entire fence.  Any ideas as to what they might be?

Trouble with beans is you put the wrong kind in and before you know it, theres a cascade of giants, geese and golden eggs raining down on you from above.