Hi Mike, we freeze dwarf French beans and have no problem. What we do is harvest them when they are about as thick as the “thin beans” you see in the supermarkets. I top and tail them and cut into roughly 2″ lengths and the give them a good wash, leave to dry for about 30 mins and then freeze on a tray for about and hour then into a air tight zip lock bag making sure I get every bit of air I can out then back in the freezer.
We tend to cook them with peas we have harvested and frozen in salted boiling water for 5 mins max come out with a slight crunch and still a luverly green colour.
We also use the tray method for freezing chilli and sweet peppers that we cut to size ready to use in stir fry sources
good luck