bean size

Does anyone know if the size of the bean you plant has any bearing on the plant that comes from it?
This year I bought some Scarlet Emperor Runner Beans (nom nom) but the beans I've saved for next years sowing are two or three times the size of the ones I originally bought. I had an ok crop in a poor year but I'm new to growing veg and made the mistake of planting so many plant that I couldn't find the beans. They set seed and stopped producing. (I have an allotment now so space will not be so much of an issue next year.)

 

The beans you buy as seeds are dehydrated, so they they shrink to about a third of their proper size.

I planted loads, and a days later the birds had dug some of them up. Those beans had tripled in size since I planted them too, just because they'd had chance to soak up moisture and rehydrate themselves.

 

Thankyou