Hi Claude
The fuel tap is not original for a Victa Rotomo ,the Victa ones are machined where the fuel hose fits and your
one has a removable brass union and removing your union is a thread that Victa don't have.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=47908&page=allNo, the main carby body for the brass nut carby is not the same as the ones with a clamp.
Pic of the carby for a brass nut below.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=34931Not sure on the starter pulley but it could be very early model 1. It's a little difficult to prove the early drawings are correct.
The model 1 throttle controller pic below.
http://vintagemowers.net/mower_victa_model_1.phpCheers
Max.