When it comes to Quality Control checks, there’s no definitive number of how many checks are expected. The official DVSA guidance currently states:

The frequency of checks may typically be expected to be 1 per tester every 2 months. However, this is based on the average garage throughput of 2 to 3 tests per day for experienced testers – so should be varied to reflect the volume of tests done or any other special circumstances – such as the experience of testers.

Therefore, a VE is likely to expect to see a QC check record that goes hand-in-hand with the number of MOT tests completed at your garage. For example, if your garage is completing double (or more) than the average of 2 to 3 tests per day then it is expected that you complete a QC check at least once every month.