Seems like I was wrong...partially.
Just had a quick Google search, seems BBC released Series One sometime last year on their online store - https://www.comedy.co.uk/shop/news/2509/the_real_mccoy_series_1/
But BBC store is now closed towards the end of last year, so wasn't up for long.
And that was a 5 year "campaign" of pestering the BBC to release it - http://www.voice-online.co.uk/article/woman-who-started-bbcs-revival-real-mccoy
And in '97 released a VHS with selected sketches - https://www.amazon.co.uk/Real-Mccoy-VHS-leo-chester/dp/B000057QVQ
But other than that it seems nothing.
They need to just do a boxset with all 6 series or at least re-run it. Since it came off air I dont believe its been back on, where as the likes of Desmonds as you mentioned has been re-run on different channels. I dont know the viewership of Real Mccoy vs the likes of Desmonds, but surely there is some TV network out there that would pick it up.