How to make my bunnies more affectionate?

I've had my rabbits 2 years, I got them from 7 week old. They turned 2 in January and are both brothers. They are very spoilt we bought a hand built made to order hutch that is 5 foot by 5 foot with 2 stories, its so nice it has real wood flooring inside. They also have a large run in the garden as it is not secure. Anyways, they've never been well too fond of me, I mean I can pick them up and cuddle them but I always get the sense they do not like me very much. They won't take treats from me or anyone. One of them bites sometimes but I'm not sure if its in an agressive way. Is there anyway I can get them to know me better and be more affectionate because I never know how long I'll have left with my little lop,lionhead crossbreeds.