Well, as others have said, divorce does not exist in the Philippines.
It is POSSIBLE to get an annulment, but it takes a deal of time and money.
Your lady will have to return to the Philippines on the expiry of her student visa (a word of caution, here - she should NOT overstay if she ever wants to return to the UK legally, as overstaying, without a brilliant excuse, like being in hospital at death's door, will get her a ten year ban - I kid you not!) unless you choose to marry whilst she is here, in which case she will have to provide evidence that she is free to marry - i.e., if she was married before, an annulment.