Agree with BEagle about BUPA - I joined on leaving the RAF 18 years ago and pay similar to BEagle with my RAF discount, despite a couple of minor claims. And their hospitals are so cosy!! But I have noticed that my premium increases are (understandably) picking up pace as I approach my dotage.
I suggest that you dig out your back copies of Which? to check who is doing the best deal as there are plenty about. I seem to remember that BUPA didn't - by a long way - get top billing in said publication a few years back.