Question about my indefinite to remain

Hello Guys,
I wanted to know if i can get back my indefinite to remain if i were away for more than 2yrs and the other fact is that, it was on my old passport during that time and when i renew it, i haven't got it stamp.I do got my Home office ref num.so is there any way for me to get it back, as i were away for more than two years, Thank you.

I think it's safer for you to apply for leave to enter from your home country when you come back in case they refuse entry at the port. Read from paragraph 7 onwards at this link - it may help you understand the ramifications better.