General   (General discussion, talk about anything.)

To play the devil’s advocate……

For £30ish busy people who lack time and the ability to carry out simple tasks, which is the majority would have said thanks and appreciated the garage saving them the……

Time and costs spent out and about finding and buying the parts
Time and effort spent fitting them
Time and costs taking the car back for a retest and waiting for it to be completed.

The only mistake the garage made was in assuming you were one of them.