i think if you earn £18,600 it doesn't matter, under the old rules it probably would have added to your risks of refusal, but better to be safe than sorry until we hear from people who applied who were overdrawn and got their visa or who were refused for being overdrawn,(thou i cant see them just refusing you for that, probably just a secondary reason)
at the end of the day they dont want your wife to have recourse to public funds.
