Hi, that’s understandable really, the cam pulleys are on a taper with no keyway, there are no timing marks, and apparently the pulleys are not perfectly circular either! The latter apparently to reduce load on the belt. Modern engines just get more complex, different beasts to when I started my apprenticeship in ‘73 that’s for sure.
I like to keep a rolling maintenance plan, although the car is low mileage, it does do a couple of Italy/Austria trips a year (or did until lockdown!)