I dont know how light the cottage is but dark grey carpets could darken it quite significantly. Why not try a pale'ish dove grey or a greige? For the "wet" rooms, you could try a vinyl floor? Having the flooring in a similar colour throughout will make the space feel bigger so maybe a stone effect to go with the carpet or grey'ish timber? It's also cheap to update. White only works works in rooms with plenty of light. I'd look at the light in each room and go for pale neutrals in stone, chalky white, grey etc. you could always mix and match paint with a couple of feature ŵalls so it's still economical or maybe a neutral textured wallpaper in the lounge for example?

They do tiles that look (and I believe made) from brick so could find some which match existing. If you want like Hardie weathers boards this wouldn't cost much for such a small area. Especially if install yourself. Easier than you think for a simple area like this, there are YouTube videos. I want to do my detach but is 4 sides, 2 levels, corners, windows etc, so won't be doing myself and been quoted £17K! But I have about 20x more area to cover so my guess it this would cost you £1K.

Do you mean wood panelling? It looks good in pale neutrals from off white to grey-beige like Elephants Breath, but colour choice will depend on how you will be decorating the room - is it modern or traditional? Panelling usually suits a more country style. I’ve seen panelling painted in dark grey and deep blue, but I think it looks much better in a paler colour.

I would do a large print or picture on the right hand side of the fireplace or perhaps a stinning Mercury glass mirror then the other mirror central above the sideboard with a long narrow picture either side xx Blanco Interiors Ps stunning room