She has to wait until she gets the FLR visa. As far as I know, Fiancee' visa in the United Kingdom will give her permission to stay here for six months, but she must not work.
If FLR visa application was approved, that's the only time the wife or civil partner will be given the permission to live and work here for two years. I know some people who already tried to work with just a fiancee' visa on their passports but this can be treated as violation of immigration law when caught. Better safe than sorry.![]()