on a salary high enough to entice him to relocate from Canada
I have to quote this as well because it raises all sorts of interesting questions.
Firstly, financial enticements may not have been uppermost in his mind. Was Jess' father ill before they left Canada? (I think he was but may be assuming.) Either way she was obviously very keen to return and may well have driven the upheaval - possibly putting newspaper job adverts in front of him.
Secondly I can just see Rob being happier in a foreign country where his place in the class hierarchy was perhaps less obvious. Once back on British soil he'd feel his lack of status (compared to his more favoured brother?) rather keenly. I've often wondered why Jess put up with him in Canada; it may be that he was slightly less nasty far from home. (Vague recollection of some conversation between them about new starts - we never found out why.)
It's clear that status rather than mere money is iressistibly calling him. No one at Bridge Farm is rich (and Peggy's money, divided, is hardly billions). He could surely earn far more employed in another manager's job than he can embezzle from Bridge Farm. But he wants to be Lord of the Manor, hanging out at the races with Justin and cocking a snook at (the inevitably lovely) Miles.