Hi there Mr. Tickle, all your questions has been discussed already in this forum, you can use the search and you will find informations that will answer all your doubts and you can also use all the links that Admin posted for more detailed information about all the visa types and immigration rules.
Yes it is difficult for a Filipina to live in UK the best way is you and her get married and she can get a spouse visa. A spouse visa will allow her to work once she get in UK.
Goodluck to your homework!!!