Although I haven`t worked for Air Wales, one being 6`2 kinda kills the idea in one shot. However, being a small airline it`s most likely have the usual pros and cons, of any small company in any line of business.
Small airlines tend to me more "hands on" and the pay may be quite low, routes and schedules not overly interesting. Air Wales are quietly expanding.
If your wife is limited to where she can be based etc there is nothing wrong with giving it ago. You only live once so you might as well make the most of it.
Don`t worry too much about names of who to write to.
Cabin Crew Recruitment, or Cabin Crew Manager the CV /letter seems to get to the right person.
Good Luck.
Others to look at Scott Airways, BA Citiexpress, Eastern all operate small planes.