Back on this again finally. Turned out the minor injury was actually caused by a faulty walking boot which has been sent back to the manufacturer with a gift of cow excrement all over it. Couple of weeks in some trainers (sneakers for the Americans) and I'm good as new.
Thanks again for all the replies. They have been digested and sorry, engineer hat on, poked into a Kepner Tregoe decision analysis model. I researched and weighted all variables across weight, mass, battery life, lens quality, lens selection, resolution, dynamic range, usability, workflow, storage extensibility, weatherproofing, ownership risk, video support, photo support, optical zoom, image stabilisation and printability.
iPhone 13 Pro clear strengths: weight, mass, battery life, weatherproofing, ownership risk
Z50 clear strengths: lens quality and selection, resolution, dynamic range, usability, storage extensibility, optical zoom
Ranked accordingly, the Z50 scores 277 whereas the iPhone 13 Pro scores 240.
In that case the Z50 has a roughly 15% rank gain for an expenditure of approximately £1100 (16-50 kit + 64gb card is fine for my requirements). But looking at the key strengths, the compromises are very very very much in favour of the Z50 being a very good camera and the iPhone being a very small and efficient camera.
I have ordered an A3 sized print and a couple of 10x8" prints of stuff I've posted in here and will see how they come out. This will shape the final outcome.
Of course the moment I make a decision, everyone will instantly have sold out of the damn things ?