your right about the dependent visa for a spouse of someone on a work permit, or for an elderly relative.

but i think if your spouse is a British citizen it would be refused because its the wrong type of visa, you would have to meet the criteria for a dependent visa sponsor, also even if you did manage to get one there is no advantage i can see over a spouse visa

its possible the embassy issued her with the wrong visa, and this was corrected when i take it they applied for FLR(M) .

what you've posted doesn't make sense, but its always best to go by the rules, and like i said there are no loop holes.