If you take a look at UKBA immigration directorate instructions - Section 4 - Annex S (ENTRY CLEARANCE FOR THE CHANNEL ISLANDS AND ISLE OF MAN)
you'll see it's stated under para 1 (Issue Of Entry Clearance) that:-
It should be noted though that due to a number of administrative reasons, that Guernsey Immigration has the final say in the decision and not the UKBA.
It's often been suggested here on this forum that such applications may actually require an extra 3-6 weeks to process rather than a shorter processing time.
I'm not suggesting that what you've been told by Guernsey Immigration is incorrect, just stating the rules as published on UKBA website and information given on the forum.
Might be worth considering to give Guernsey Border Agency a call to double check on current procedures and expected time scales etc.
I can understand your frustrations of waiting so long.
One of our members (Louis) actually had to endure a full 12 weeks stressful waiting before his wife received the good news of visa approval.
Don't forget that during the past few weeks there has been quite an impact on normal working times in Philippines due to holidays and elections.
Good luck for a positive outcome asap.