White-matte cabinets (flat panel, not shaker) and white bench (or maybe epoxy sealed marine ply??...siriuskey can tell you about that), mirror splash. Love the ceilings. I personally would go for a modern, stream-line, no handles, integrated appliances look. This space has real potential to be very cool, even with the slate. It doesn't need any more more texture or darkness. This is a nice kitchen, you should be able to sell it on ebay.

To Modernise this without rendering or retiling the roof I would probably recommend to go darker with the trims. My top pick as a colour consultant would be Dulux's Domino for the trim. It will be a little bolder and create a more modern contemporary feel. You can see it pictured below as the trim. Obviously this house has painted their bricks in the shade "teahouse" however it will still look much better on your 1980s "peru" colour bricks! Don't hesitate to contact me if you need any more help colour wise!

consider a similar colour in a shade darker than the timber trims...if the plinth is exposed to nearby lawn mowing or garden beds the darker colour is more forgiving of dirty marks and makes a better background for planting

Paint swatches are your friend here, either sample pots or the A4 size that Dulux introduced. Paint looks different in different lighting and surroundings. Our, barest touch of blue, interior paint, has one wall that throws a bit grey in certain light - the one thing I was trying to avoid - but is perfect everywhere else 🤷🏻‍♀️ . The initial favourite, while the paint chip was very similar seemed over saturated. It’s definitely worth a visit to the paint specialty stores, many have colour consultants, if you’re still undecided. We also found them less expensive, too.