With the number of sailboats and motorboats at shore in Ottawa area, I'm certain you can find recommendations for a fiberglass specialist that can fix BOTH problems at once.
I suspect your door to be out of shape or your hinges to be the wrong size or out of ideal position. Door gasket may also need to be adressed. Most RV shops are likely to sub-contract their fiberglass work, which explains the high cost and poor results in my humble opinion.
Such technical repair It is likely to be expensive, because it is labour intensive, but with Bargman L400 locks getting so rare, price of spare parts is outragiously high: no matter what, unless you invest time to learn and a few tools, it will cost you a few hundred $ to get a door that fits and a lock that keeps it safely shut. You can likely bring your RV for an estimate, to reduce chances of poor fitting. I strongly suggest you look for marine composite and fiberglass repair specialist. Marinas, especially sailboat forums could be good sources of referals. I asked for help in a local sailboat forum. If you can't find using the sailboat resources, let me know. As soon as I have some response I will forward it to you by private mail.
Marine repairs as RV door repairs require excellent structural integrity and precision to last and work properly. Fiberglass repairs require far more time than material cost. The whole repair and finish operation would take a few days to be completed, one step at the time. Your door would need to be removed, hinges to be possibly repositionned, lock fitted. If you are a handy man who don't mind reading instruction manuals and documents posted on the Internet, you can possibly do part or all of the repair yourself. The tough part is really the finishing touch. Once you are satisfied with structural repairs and fitting, you can sub-contract the paint
job to a local automotive body shop if you want perfect finish.
If you dare to attempt such repair yourself, or at least part of it, have a look at the other thread on this forum where I have posted clues on the material and tools to use. It requires more time and patience than anything else. It is quite rewarding too.