£10 is the cash in hand price.
Pay by card then £20 a corner.
If they are taking cash like that then it probably is a tax dodge. But thats the tax man's problem
Not really as lost revenue means losses elsewhere.
It's much like the smug **** across the road from me. He's out right to the end of his driveway partner by his side every Thursday clapping swinging side to side telling the whole street they are proud to support the NHS.
Yet he doesn't pay vat, takes cash in hand, has at least 5 family members working for him too off the books.
However that's the British way it seems. Everyone out for themselves. They call it "great" Britain when the place is a cess pit filled with ignorance and contradictions.