Absolutely correct. In this instance, you have given consent for the staff of the service centre to power on your vehicle and even drive it around to get it inn to the service area. They will also take several measurements of your vehicle such as tyre tread depth, brake pad wear, fluid levels, date of registration, and the mileage to ensure that the correct serviceable parts are replaced for the age and service life of the vehicle. You explicitly consent to them collecting and storing this information as part of the works carried out on your vehicle, in keeping with their policies for how they use this data. This policy states that they may (will) sell this data to insurers. These are the terms of business, and if you don't agree to them you are welcome to take your vehicle elsewhere. The others will also have the same policy, so you'd better be able to source your own diagnostic equipment, or be willing to drive cars made at the latest in the 90's.