PAT is one of those jobs which in its self appears not to be that inspiring. The temptation is to rush through each 'test' and stick green labels all over. The key, of course, is to inspect and test analytically. The more experience you have the more noticable defects will be upon inspection.
I used to take on anything from PC's to arc welders, commercial ovens, compressors workshop machinery and fridges. An example might be a couple of newish microwave ovens for a comercial enterprise. After IR testing I was able to predict that one was about to fail. Within a week it had.
For this type of work I do not charge 50p/item. I charge by the hour.
I include all types of equipment both single and three phase equipment, plug-in and 'hard wired' but not equipment covered by specailst maintenance regimes such as CNC machines, large motors, generators and alarm systems,
You could make a profit in specialising in problem solving commerical equipment.
But if you do I would suggest that you do not work for somebody else.