I am sure you are right, but it is the operators responsibility to ensure compliance, so its worth a check.
The CAA document has a big list of items they believe certification is required for and if contemplating a spray its worth a read anyway.
If you ignore it what then?
Probably bugger all as the CAA seem to have lost all interest in maintenance related issues.
However your insurer might be interested in the event of an accident.
As always caveat emptor!!!!!!!!!