I think you are probably wasting your time trying to advertise in the U.K for a property like that.. The agents operating from there (UK) are usually found at British/Filipino Barangay fiestas etc selling cheap house and lot plans.

Your best bet is too put it on here..

http://www.islandsproperties.com/properties/

Pay for their Gold advert plan for maximum exposure and see how it goes..

There are also tons of free advertising Philippine based web sites that you could put it on..

Anyone looking for a property like that will probably end up seeing your ad.. It just takes time..

Good luck.