Luke's not worked out that Mike caused Luke and jess to split just to move onto the next girl thus making all that shit for nothing
Tbh I just think it's not that deep. Luke wasn't massively into Jess, and he doesn't strike me as the type to hold grudges. Maybe he feels Mike did him a favour. Or, he realises in that environment you can't hold onto any animosity as it's too small, too confined. You just have to move on and make the most of it.
Does anyone know why they aren't really using the hideaway this year
I'd guess it's because other than Finn and Paige there's not really any other couple to go in there. That might chance now though.