Just an update. I removed the screws holding the bottom hinge against the frame with the intention to place a few thin washers behind it so hence pushing the door up a little. I noticed behind the hinge they originally put a piece of cardboard to create a space and i'm guessing this has got squashed thinner over time. So i added the washers and tightened the screws. I also filed down a bit of the strike plate and so far seems nice and smooth. Will monitor how it goes.