Smoo I think they must have picked up on the fact you don’t know much about what’s needed?
when I had my Audi Rs6 and 4 the forum I was in, we would scan or change code in other members cars for petrol money if needed a full scan would take about 20 mins, if something needed coding then a few minutes if you known what you’re doing.
charging £300 is a bit steep.
Where abouts in the country are you?