Incidentally, if Teller start to get an appreciable proportion of the UK population (remember, users will be using Teller without realising, through other apps

Incidentally, if Teller start to get an appreciable proportion of the UK population (remember, users will be using Teller without realising, through other apps and platforms), they should expect a call from the regulators, who will want to be sure that they can't cause any systemic instability (eg by getting hacked.)