She must apply for this visa in her country of residence.
She seems to have only a visitor in Dubai so she's not residing here (and if she's working ... it may be illegal work too as she seems not to have a work visa).
So in this case, I'm afraid there's no other way than starting the process with the British Embassy in Manila.
In my opinion, it will be safer (ans less costly) for you to pay the flight back and the visa processing in the Philippines rather than accepting the sponsering (and safer too, as you have to be sure you can trust the sponsor; if for the moment he employs illegaly your wife, I would be doubtful!).