The first person you should call is a local interior designer. They can go through the bathroom with you and see if your issues have merit. They can then come up with a design that fits in with the look and theme of your home. The reason to hire a specialist in interior design in Newcastle is that local designers know the area. They know what is selling and what is turning buyers away.
Therefore you can work with them to come up with a way to make your bathroom more appealing. You might want to make it look more specific to your own tastes or just make a nice general all-purpose bathroom that is fit for a future sale. Either way, you should absolutely contact a local interior designer for some professional insight.