Ah, Hache, I envy you. She is already here...
How long is she allowed to stay? Long enough to apply for permanent residency? Then she could just stay longer, become a UK citizen and divorce. Becoming a UK citizen = losing PH citizenship = she would be a foreign national in the Phils. The Phils do accept divorces by foreign nationals, you'd just have to wait long enough to get UK citizenship before she can divorce.