If you don't do something stupid you should be okay. I would avoid some of the provinces like the southern island of Mindanao and the Sulu Archipelago which are of particular concern.
Now is the time to plan on how you will handle your money. Will you be using a debit card and getting cash from ATM's? Or, will you be carrying thousands of pounds so you make yourself a big target for thieves? Will you be staying in cheap hostels or hotels with private rooms? How much can you afford per night for a room?
You must also figure out on how to actually stay in the Philippines because from the UK you get 21 days free at the airport. You just can't show up and stay as long as you want! Make sure your passport is current and has at least 6 months remaining before you leave the Philippines.
You can get some other advice from these travel forums:
http://www.tripadvisor.com/ShowForum-g29…
http://www.lonelyplanet.com/thorntree/fo…
Some girls will come up to you because you are a rich foreigner overseas and they would like to separate you from your money! Otherwise you will meet some nice people who only care for you and not your money - perhaps only for a short while though!
Is this your first time visiting Asia? Have you been to India or Thailand previously?
Expat forum:
http://www.alloexpat.com/philippines_exp…
Good luck.