'If you need a top-up just pop in, sit down with some refreshments and relax - we’ll take care of it while you wait for just £9.99. We’ll even wash your car for free during your visit.' You will go when the low level message comes up so possibly needing about 15 litres having done about 10k miles and your car may be coming up to a year old or more. If this does include the adblue then it does not seem too bad unless they only do a top up and not a full refill. But then whilst having the relaxation, refreshments and waiting for the car wash, you are bound to look at the new cars and it could be expensive.