I know what you mean about being a tight git, we do buy a lot of our seeds like runner beans and what not from the local Wyevale garden centre when on a sale. Some varieties we buy from seed catalogues though.
I buy some of my own seeds for the allotment from ESK, and their own country value...
To be honest I don't do the seed buying at work so not sure. However, I checked some of the places we order from and Thompson & Morgan have 'Black Russian' in. Looks very very similar from that photo but not sure that it's exactly the same variety with a name change as it's a heritage...