Your lady can complete the divorce in the UK if it has already been filed, that will be recognised in 99% of countries, but not the Phil. This leaves her free to marry in the UK.
However, if she applies for a spouse visa she needs to show she is free to marry, now whether the UKBA accepts the UK divorce, I don't know, although I'd imagine they would otherwise why issue it?
To prevent any issues in the future she needs to get an annulment in the Phil.
One word of advice, don't get a tourist visa to visit 'friends' when she is actually coming to see you, if the UKBA finds out this can cause issues in the future. You need to visit her in the Phil as proof of relationship for any future spouse visa.
Can I have some Rep now no one ever gives me any