As Joe says, getting visas for ones children to come here is never as straightforward as some might think, especially when they have been left with family in the Philippines for a long time. The longer the children are left in Philippines and cared for by others, the harder it becomes to prove sole responsibility and to make a strong case for allowing them to come to the UK. Personally I always think that it's best for the mother to do this within a year or so of arriving here herself.