It sounds to me like he likes you.
If you and he both don't care that he's 2 years younger, then it doesn't matter.
Distance relationships CAN work, so don't let the fact that you're going to London get in your way. They are not easy, and as with any healthy relationship, they require trust and loyalty on both ends, work, and open communication (that isn't to say daily communication.) The distance just strains these.
Best of luck.
