If you do it terracotta, you already have the darker wood furniture (which works better than pale) and some grey pieces too, plus the modern black painting would look amazing. I would consider mixing things up a bit, such as some edgier wall lights and some really modern items. I don't really believe that certain colours are more suitable than others for a space, ie. terracotta is a 'traditional' colour, a colour either works or it doesn't. I would put money on it that ochre and terracotta are coming back anyway, they are the natural antidote to grey!

Hi. Have just put a few colours together. But the absolute best way of starting to choose colours is to measure the colours of your fixed finishes first. (Flooring & cabinet) You can do that with a tiny device which connects to an app on your phone. (approx £55 on Amazon) It’s similar to taking a snapshot but it measures key attributes of colour. In particular to which Hue Family it belongs. Once you have that info, it’s possible to locate & plot the colours on the Color Strategist Wheel. In doing that you have a reference point for searching for paint colours to create harmonies with your finishes. So choosing colours from the same Hue Family would create a monochrome palette. Choosing colours from the opposite Hue Family would be complementary etc. (It takes a whole lot of guesswork out of finding paint colours) 🌈

It will make the ceiling look lower, how much depends on the contrast with the wall colour. I assume by making the ceiling lower it will also probably make the room feel smaller, eyes tend to alight on horizontal lines. Why not just add the coving, you can get ones that project onto the ceiling more so it won’t make the walls feel lower. paint colours can help, either choose something that reflects a lot of light (Little Greene’s website for example details the light reflectance value of colours) or alternatively a really deep colour which gives the walls depth. A lack of contrast in paint colours also helps make the room feel bigger so wall, wood and radiators in the same colour or just a slightly lighter version. Furniture choices help too, furniture on legs so you can see the floor beneath make the room feel bigger or a glass table or cane armchair that doesn’t visually fill the room. A sofa that doesn’t contrast a lot with the walls will help as will a large mirror and curtains hung high to make the walls taller. There are lots of ways to make it feel bigger

plenty of room i'd say! i'd stick it in the bottom end behind a wall of tall units for the kitchen (fridge, freezer, oven tower, pantry) and then have base units only along the wall facing bay window (to keep it bright and airy and maximise the width of the room as much as possible). then the bay window could be a lovely built-in seated area for table, or there's space for an island and then the bay window becomes circulation space. the top end looks like glass all the way round? so assuming dining table would go there - but if you did the window seat and table then that could be seating area instead.