Now that Canmore has been replaced by trove.scot, as previewed here, the result looks unfortunate. Although HES have retained the same index number for items, they have not provided a soft-landing transition.
An enhanced Wikipedia template does make conversion tedious but feasible. For example
{{cite web |url=https://canmore.org.uk/site/123987/whatever |title=Whatever |publisher=Canmore |date=3 July 2013 |access-date=15 February 2017}}
using a new place parameter to become
{{Historic Environment Scotland|cat=PLA |num=123987 |desc=Whatever | num2=NN12SE 3 |access-date=25 June 2025}}
Simpler are those using the old Canmore template, more complex are those using raw URLs (including a fair number still with rcahms in their Canmore URL.