A couple of dozen is a lot...I can spare about 10 if you are interested. They are sourced from Greece (second generation), so if there have been any breeding improvements by seed companies, these won't show them.
They are very robust and contain about 4 fat seeds to the pod when grown. I have had 99% germination from them this year, and my seedlings are a foot tall and jumping out of their loo rolls.
Do you have anything to exchange? Eg interesting climbing beans (not runners)? Then we needn't worry about p&p.