No flames from me at all.
I would definitely contact this man. Why not. You don't have to do anything with him, perhaps have a coffee, get to know him?
Your line: But while I'm sat here alone on yet another boring Sunday because BF is sat at home in front of his play station, STILL not ready to commit to moving in with me, I am filled with curiosity. REALLY hit home with me.
Sweetie, your BF will not change. I am not saying to throw 4 years away, but life passes you by VERY quickly, and why sit by waiting for your BF to suddenly want to move in with you. When DH and I were dating, we spend EVERY single moment we could together, and we both wanted it this way.
Before I met DH I was dating someone that sounds EXACTLY like your BF, and I would do anything he wanted, go out, sit in, wait for him, etc. Thank god I grew up and grew wise. He is alone today, and probably playing playstation himself..
I would consider calling this man, see what happens.