Ah yes...but the goods he carries, are fitted and sold.
And the cost of hiring the aircraft to fly out to the job would be billed to the Govt Dept /whoever that wanted the plumbing job done.....so there is a charge for 'carriage' of the goods, fitted and sold.
All these things, upchucked by the 'regulator'/polisman depend on the spleen of the day/or lack of interest , or otherwise of CAsA persons.
CAsA's great consistency is its inconsistency in the application of "rule of law" or more specifically in their case. their 'law of rules'
Believe me, its a sh*t show.
Different strokes for different folks is rampant.