I am based in the UK and have been working in industry for almost 3 years now since graduating. I have very recently left my first graduate job (no bridges burned) and have been working in a new job for the past month (both small businesses).
I have decided before that I want to study for a Master's degree. Originally I was going to do it full time but after a series of events in my personal life I have decided that part time study would be the best option for me while staying in full time employment (most likely over a 2 year period in my free time). My new employer doesn't know about this yet.
On applying for the Master's degree, the universities I am interested in require that I have a professional reference if I am in full time employment.
I am unsure who to ask for the reference. I don't know if a new employer would see me in a negative light for not mentioning this to them before starting employment with them (I don't know if some employers see this as not focusing on the current job or their business) and I would have only been working there for a few months when it is time for me to send my application.
My employment with my old boss ended on good terms. On my current work history I have been at my old place much longer than my current employer.
So my questions are:
When applying for part time study and need a professional reference, is it better to ask my current employer or my previous employer? (who I have had the most professional experience with in my career so far).
If for example I do ask my old employer for a reference, should I mention my part time study to my new boss?