Am thinking that the doors into the corridor and bath are taking up valuable floor space, leaving the corridor an underutilized space. If they could be switched to a slider, barn style door you could use the space maybe as dressing space with wall hugging shoe storage or if there is enough depth - add a closet. The front entry is a space which isn't doing double duty, if it doesn't compromise the entry door and heating, the wall between the entry and bed space could be taken down (with proper consideration to the construction), giving another area to work with.

If you are going gang busters and looking to do more than just tweek, I would consider swapping the kitchen to the bathroom / closet area so that the living/ kitchen are what you enter into. You could then make more use of the entry area. The bathroom moves to the kitchen, so the bed/ bath are not walked through and are set at the 'rear'

If you look at the space as two halves. From the door you could walk into an open plan living through to dining then kitchen along the back wall. The right half could be your bedroom and bathroom with ample space for storage running the full width between the two. Are they the only windows? If yes I would be tempted to have the bedroom to the rear with the window. The corridor and closet might just be ample for a shower, basin and toilet leaving you with a good sized bedroom. Pocket doors are a good idea if space is limited especially into the bathroom.Could you move the boiler into the generous sized hall? Much depends on supporting walls and plumbing.

I agree with keiblem. Living-kitchen on the left and bedroom/bathroom on the right. It makes the best use of the windows and floorspace. You could make the entrance a utility room, move the boiler and fuse box (if possible) and have space for laundry, coats, outdoor wear and shoes.