They were doing great indoors until I transferred them in to the garden. Now they are all dying. Does anyone know why this is?

There are a number of fungal diseases of runner beans, mo. Also, there are a number of pests which can attack your plants. Without describing what the symptoms are, there is no way of knowing what is wrong with them.

Can you post a picture perhaps?

There is a useful site for questions like this at Allotments4all and there are many knowledgeable folk posting on there.

Also, it's not too late to set some more which should crop well in September. Good luck!

Thank you Monika. I shall have a look at that website.