Greys would look good in these rooms. I wouldn't paint the paneling. Rather than a mirror over the fireplace a large scale painting would look good.

The front door is around the other side by the way! The windows are aluminium so cannot be changed. It is all rather ugly at the moment.

I agree you probably need to centre the vanity and the cabinet on the wall or they could look a bit odd! You don't say why you don't want a space between the window and the vanity - just my opinion, but I would think 300mm could be quite useful for a bin, a clothes basket or box, or a small stool for putting clothes on? The only alternative to leaving a space, is to fill it with something as the response above suggested. To avoid it interfering with the window, you could make this something lower, so it sits level with the top of the vanity. This could be built in and the wall lining put over it to create a single "shelf" level with the underside of the vanity top, or if you can find some freestanding open shelving of the correct width, which could also be cut to the correct height, you could wedge that between the wall and the vanity side when fitting the vanity. Just bear in mind also, that you'll lose some of your towel hanging space if you put something too high in the space.

Hello, in our home under each window in the wall there is a recessed space. We are looking to pack this out so it is flush with the rest of the wall and also insulate the space. Has anyone else done this? Would love to see some finished work so I can get some ideas about how it will look