I have a Norwegian passport but I live and work in the UK.

Hi,
I have a business meeting in China on the 24/04/2017 however I am having troubles with my invitation letter, also I want to apply for a 2 year visa.
My Invitation letter states i should apply from Oslo, Norway and if i were to get a new one I'd have to have a strong explanation as to why I can not apply form Oslo. Plus the letter also has 3 months validity.
Also, I have been told my chances of getting a 2 year Visa from the UK is slim. Will I have a better change of getting a 1 or 2 year entry if I apply from Oslo.

hope all this makes sense.
Thanks
Oyv