Hey man! Really appreciate the feedback.
I should have clarified my lighting setup a little clearer, my apologies.
Sorry, when I said I didn’t have any other lights in the scene, I mean’t like spotlights, point lights or rec lights which could have been clashing with the main directional light.
I have also gone through and checked everything is set to moveable and that raytraced shadows are enabled, which they are and unfortunatley there is no difference in the scene.
I’ve also noticed that I am getting splotchy shadows around the scene. The worst is in one of the upstairs rooms where it looks a real mess.
I can’t put my finger on what would be causing this. 
Edit: I also thought it maybe the glass in the window having some issue with light refraction, but ive hidden them and its still the same! The plot thickens!
Anyhow, if you have any other ideas, would be greatly appreciated!
Cheers, Jon