I think it is charming the way it is and if you put some big birch branches or something sculptural in there and some contemporary natural wood pieces or primitive art in the living room, it would all blend together. Please don't take out the windows--that will affect the whole face of the building. Rustic and modern is mixed all the time and can look terrific and give the place a little character. I think the Europeans do it particularly well. You could tone down the mortar with a stain. Unless it is in bad shape, repointing is messy and expensive and tough to do well.

You have used grey as a neutral, and it is a backdrop for your co-ordinating black and white photos. It is perfectly fine to stick to this neutral palette without adding any colour, but if you do want to add colour, then the brighter the better. A mustard yellow, an acid green, a raspberry pink or a plum would look good, as would a strong teal. If you want to use primary colours then use them sparingly to avoid it looking like a child's playroom! Perhaps have the print and then pick up one if the colours in a few accessories, but don't go overboard with it. Primary colours can be very jarring to the eye.

Thanks for replies. I'm not an expert in any shape or form but I have decorated and furnished our georgian home which we bought recently so have outlined my thoughts. Symmetry is key to georgian design so would have matching sofas (classic style) either side of the fireplace with a coffee table in the middle on an oriental rug. A pair of wing chairs would also look good but appreciate you want to minimise! Sage green or stone may work well with the curtains or try a pale duck egg (it's difficult to see the exact tones of the curtains). Georgians drew on oriental design, Chinoiserie wallpaper is very in at the moment and Is typical of the period. They also used black lacquer, maybe consider white oriental lacquer furniture as a modern touch? I would put a picture rail in the lounge as it looks as if you have one in the dining room so would carry it through. The lounge would look lovely with a large chandelier. Maybe accessorise with Roman busts, large ginger jars etc. the parquet sounds lovely. They are lovely rooms anyway so I am sure they will look stunning

I think tan leather would look good with the mango furniture. I'm not sure that mid century would complement your furniture, Chesterfields are fashionable and fine for modern homes so you could go down that route. Although I think something like this would look great: http://www.made.com/canape-3-seater-sofa-saddle-tan-premium-leather. Decor wise with tan leather cooler colours work best - blues, greens and greys. I love olive green with it - you could bring in as an accent wall if light is an issue and copper accessories would look great with the olive - Next has lots of lovely copper stuff in at the moment.