The MOT test itself is identical in every Perth & Kinross garage — DVSA writes the manual and every tester works to the same checklist. What changes from garage to garage is the price and how the result is handled: a cheap loss-leader test is priced to bring cars in for billable repair work, while a fair-priced test should come with a straight explanation of what actually needs doing and what can safely wait.
If your car fails in Crieff and the repair is done at the same garage within 10 working days, the partial retest is free. Leave it longer, or take the car elsewhere, and you pay a full MOT fee again. Advisories are not failures — they are early warnings, and a good mechanic will tell you which ones matter before the next test.