1 Year M visa & M type extension

Hi,

I am currently in China on a 14 day single entry M type but I will need to be here until Feb 3rd. Is it possible to extend my M type from within the country? Also, I am likely going to be travelling to and from China frequently for the foreseeable future so I would like to obtain a 1 Year multi-entry M type. Could you tell me if I am likely to get this if I apply in my home country? I am from the UK, this is my first M type but I have also visited PRC on an L type in the past and I have previously lived and worked here on a permanent residency permit for about 1 & a half years.

Thanks

Oliver