Looked at black circles and they had tyres available with a Saturday appointment. Ordered and paid for 4 tyres costing £360. I received an email later in the day stating that they could not book me in until the following Wednesday as the garage did not have the tyres. The reason I went with them was because they stated that a Saturday appointment was available, not down to cost as they were roughly the same price as local garages. I suggest that you contact the garage that they are booking you into to confirm that they have the tyre(s). Happy to take your money without verifying stock. First and last time I will use this service.