Fathers of reddit. How can I make it up to mine?

My story is a little complicated but I'll try to keep it brief.

Growing up, my mum worked most of the time and it was mostly my dad who raised us. They divorced when I was around 9. I always had a pretty good relationship with both of them, they didn't argue after the divorce either. They lived close to each other and we could go see mum or dad whenever we wanted. Pretty awesome.

My mum met my step-dad about 2 years later. By this point my dad had re-married and divorced a horrible woman who couldn't stand me - in fact this was a huge reason why they separated she was incredibly jealous of me. My mum had got a job with more normal hours and we had the chance to build a relationship in the time I avoided my dad's home because of the wife.

Now, my step-father, who is a lovely guy is english. Him and my mum wanted to get married and so me and my brother were posed the question: did we want to remain in Brazil or go? Now, my mum spoke perfect english from a young age, my grandparents had their own english nanny growing up and both completed their phd in the UK. England had always been a part of our culture so we said yes.

I think you can see where this is going. At 12 and 11 me and my brother moved with my mum to England. Initially dad didn't want to allow it but eventually he caved and we came. We see him maybe once a year or once every two years, it varies. But until recently I didn't realise what impact us moving had on him. He's the kind of person who was born to be a father, I was in particular the apple of his eyes since he always wanted a girl and I inherited his artistic streak.

I'm 20 now and I think as I realise how much hurt and pain he must have gone through when we left I can't help but feel guilt and regret. And my father is an incredible man I feel I robbed us from the chance to have a better relationship. He's pushing 48 and more and more I realise I'll never have years next to him and the opportunity to be close to him ever again. And of course he lost the chance to shape us, input on our lives and help me and my brother goes as adults.

I don't know what to do. More than anything I want to apologise and make it up to him but how do I even approach the subject? What should I do?