Blue Eye Macro

I have started my new job now and my new employer has started to put me forward to study for a Masters degree as I have already have a Bachelors.
I only got this job because of the subject I studied in my degree (Health and Social Care; my job is Care Coordinator). So it treats as a complement really.

I have started to become keen to go through with the idea of reentering Higher Education (again) but I just want to know, whether I am authorised to choose which subject that I feel will benefit myself (my career) and my employer (their business)?
The same question goes for choosing the institution of my interest as well?
In terms of funding, is it possible for me to fund my half and my employer pays their half too or would they need to fully sponsor me?

I've started to explore the avenues about what options I could take and so far I've become more appealed to study Healthcare Administration at an American University because it's the industry/sector in a Business perspective. Unfortunately none of the UK universities offer that, apart from Birmingham City but I don't generally like the Midlands universities as a whole...
The main good thing about the Healthcare Administration course is that I can study through the Online Distance Learning route which is popular in the States, especially for international students such as myself. But just worried about the price...

The other option is Safeguarding in an International Context at UCLAN (University of Central Lancashire).
Again it appeals to me because it's Online Distance Learning course and it's totally relatable in the industry as it's an extremely intense subject as anyone would imagine so.
However my snobbery is getting better of me in terms of the institution's reputation, especially the league tables...

Does and can anyone give me useful advice that may benefit my employer and myself in this situation?

Simple, follow your heart dude. Life is short.