Great question – my students all paid via cash for single lessons, then bank transfers for block bookings / voucher payments. I would get the odd cheque now and again – but mostly it was those two formats.
I know that Matt Jamison in Belfast has been looking into a portable card machine, I will ask him about it 🙂 I also think Dave Rutherford in Middlesborough might know a little more about this type of thing.
As for cash being obsolete by 2025, personally I don’t think it will happen. The government’s main motivation for this is to ensure that all transactions are taxed properly (i.e. ending the cash in hand work culture that goes undocumented) – however, instead of ending this they risk people moving to a new form of currency (might be online) or an alternative for “cash” in real life, that would mean that it doesn’t achieve the aim that they intended. It is a huge political risk to implement such a change, that might backfire and actually decrease tax income. Personally I don’t think any future government will have the political drive to push this through – especially with the fallout of Brexit over the next 10 years being the main focus.
I might be totally wrong, but I believe cash will be hear to stay for the foreseeable future 😉