Cell phone location triangulating

I have managed to get a developer to create the algorithm and api database for uk cell towers for the purpose of triangulating GSM cell phone signal however, as the developer is new to this he cannot find out which cell tower the other (target) cell phone is connected to. Triangulating will be done using a PC software via https and just by simply inputting the other cell phone number. Is there anyone who knows how to find this out? maybe we can work together. Basically i’m looking for someone who can create cell phone location triangulation via mobile cell towers. You will have to get hold of api’s for cell towers including location and be able this in UK. I don’t know how this works so you will need to do this on your own from beginning to end. **** ONLY DEVELOPERS THAT KNOW HOW TO DO THIS MAY BID AS I WILL END THE PROJECT IF I SUSPECT YOU DON’T KNOW HOW TO DO THIS *****