Domestic visa in a private household in Scotlond

I am a Filipino, and currently in the Philippines. I have a work in Hong Kong as a domestic helper. Someone from UK wants to employ me as their domestic helper. I want to know how difficult it is to get a visa there?
I have a friend who is in Edinburg, Scotland now. She processed her visa here in the Philippines too.  She works as a domectic helper.
How long is the visa granted for domestic helpers there?  if my visa is granted, can I extend it once its over? How much is the salary for helpers?
I want to know all this because Im planning not to come back in Hong Kong and just accept the job offered on Scotland.
I hope you can help me out. Any advicr ot tips os fully appreciated. Thanks in advance!

Have go got a job in Scotland? I might have a family here looking for a nanny. If interested or you know someone let me know..
Thanks