From Public Health Scotland today:

Of all cancelled planned operations during November 2022, for NHSScotland (excl. NHS Lothian) 714 (3.3%) were cancelled by the hospital based on clinical reasons, 444 (2.1%) were cancelled by the hospital due to capacity or non-clinical reasons, 590 (2.8%) were cancelled by the patient, and 95 (0.4%) were cancelled due to other reasons. The rate of planned operations cancelled by the patient has been on an upward trend since March 2021 and is similar to pre-pandemic levels.

https://www.publichealthscotland.scot/publications/cancelled-planned-operations/cancelled-planned-operations-month-ending-30-november-2022

The performance of NHS Scotland can only be measured in terms of the 444 (2.1%) which were cancelled by the hospital due to capacity or non-clinical reasons. Other cancellations by the medics or the patients themselves must be assumed to be based on sound medical or personal judgement.

The above graph, inevitably, due to its scaling for the convenience of presentation, does not give due credit to the phenomenal performance in terms of a complex system in meeting its targets. This below does a better job on that:

A system performing more than 20 000 procedures in one month with zero cancellations due to staffing or resource shortages would require to be significantly over-staffed and over-resourced.