Thanks for your question. I will try to help.
Basically, I would not appeal and instead submit a new application
If you have not lived together in the same accommodation for two years then the home office is very unlikely to regard you as unmarried partners.
This means that you would either have to marry where she is and then for her to apply for a spouse visa OR apply for a fiancé visa so that she could come to the UK and marry you within 6 months, after which you could switch in the UK to a spouse visa.
It seems that quite a bit of time has gone by and so I would simply instruct a solicitor as soon as possible based in the UK to act on your behalf.
An appeal at this point would probably not do anything but waste more precious time, I am sorry – I know this is probably not what you want to hear – but the priority is getting her a visa as soon as possible and the likelihood of success on appeal sounds to be remote.
A work visa would not be appropriate because you are in a relationship together and so the quickest way to proceed would be either to marry outside the UK and then her apply for a spouse visa OR an application for a fiancé visa in order that she can come to the UK to marry you.
My goal is to provide you with a good service. If you feel you have received anything less, please reply back. Please remember to leave positive feedback using the stars at the top of the page.