What a statement, if you look at the statistics, they will tell you cash has picked up lately, as a means of paying. And when you get into the realms of paying SPs any other way, than by cash, you are on a slippery slope, and will get caught out. I would never let my punting life cross over in this way. Cash is King. 
As I'm sure you are aware, it costs the High Street Banks money to have cash delivered to Branches and to have ATMs serviced. They are 'for profit' businesses, and if they think they can increase those profits for the benefit of their Shareholders, which include the big private pension providers, they'll do it - remember when they stopped putting covers into ATMs? The BoE had to put pressure on them to reverse that decision.
Yes, cash is enjoying a bit of a comeback currently, largely driven by older people who are not particularly comfortable with online banking, but once they're gone there will only be people who find the convenience of paying by phone or card much more convenient.
As for SPs, they'll just go with the flow - I know of a couple who can, and do, take bank transfers as payment now and to e it convenient to them - no trips to the Bank to pay cash in - card payments may take longer, as they can be disputed by clients. I suppose the "sergei's" of the world won't like it but I'm sure they'll adapt, they'll have to.
