Hi Richard

Expensive but maybe best option eg
www.dmu.ac.uk/.../employment-law-and-practice-llm-distance-learning.aspx

Much cheaper but requiring self discipline and a lot of self reliance:

Buy yourself a good employment law textbook such as Selwyn on Employment Law and work through all or most parts of it. Better still, if you have access to any academic online data services such as Athens, ** then you’ll probably have access to LexisNexis resources therein and similarly work your way through their vastly more extensive digital employment law texts.

For applied employment law, eg barrister Daniel Barnett produces a lot of good stuff and even tutors and resources an ‘inner circle’ - for a fee of course. But such as this can bring all the textbooks to life and make them far more useful to real life scenarios ( similarly, study of actual case law transcripts can be invaluable too in this regard). You won’t get the LLM or whatever after all this but do it thoroughly and you’ll get pretty expert.and if you already can point to the MA it might not matter too much to you personally about this aspect.

** - as usually comes with any UK HE institutions academic library access for all courses not necessarily expensive ones or specifically law ones ( and I believe Open University too) and sometimes via eg NHS employment.