Downunder,
I got that many years ago, and still have same CPL and Class 1. The 'Australia only 'restriction' is actually a concession, which I think even here won't go to ATPL - so charter and instructing is as far as I got - and frankly I am grateful for that. (Elsewhere in the world, I am only allowed a day VFR PPL). However, I would guess there is no reason in theory why you could not be employed as co-pilot on an RPT dash or something. However, a mate of mine who has just been taken on as Dash co-pilot was told to get an ATPL before they would do anything with him.
Unfortunately, and infuritating as he may be sometimes, the Dr might be right again. However, don't give up, build some experience in the lower depths of GA and who knows..... In theory it could happen.