Does the 4th bedroom have to be upstairs? If not I’d consider using the dining room for the 4th bedroom, perhaps with small en-suite next to it, I’d look to see if you could knock through between the kitchen & reception room for a kitchen / diner / family space & then you still have the lounge for relaxing in as well.

Thank you, unfortunately there's a large chimney breast between the kitchen and the reception room, would have to see how much it would cost to remove, I could knock through to the dining room and make the reception room the 4th bedroom... Thanks for the inspo!!

What sort of budget do you have?

How about making the front Lounge into a new kitchen and dining room? Back Reception to be separate living room. Leaving Dining to be the 4th bedroom and the current Kitchen can be an amazing utility/laundry room and downstairs shower room (assuming coat cupboard at front door is too small to turn into shower room). Only issue is getting services to the front room for kitchen, but it seems like you're in a detached house so can be brought round the side of the house externally? I'd also have a look at opening (re-opening) a doorway up to the back Reception room via the current Kitchen as it's a bit of a hike to get there via the front room.