Hi, Charlie, This looks like an interesting plan -- what are you doing about lighting for the work surfaces? Will you have under-cupboard lighting? I know you say you don't like downlights (recessed spots), however they can be extremely useful (on a separate circuit) to have as additional worktop lighting, to make sure you don't work in the dark! Their unobtrusiveness also allows you to have the style of light fittings elsewhere that you want, which might not be enough light on their own. Regarding the ceiling fittings; I do get that different ceiling heights are a challenge. It all depends on what you want to light, and if the lights as positioned will work for your lifestyle. However, I wouldn't worry too much, and instead make sure that all areas have enough light for their purpose. Depending on the fittings chosen, you could even have one large pendant rather than the two that are shown over the island (between the RSJs); although two smaller fittings would also work, as shown. What will that single, circled fitting light? It generally works best if the light fitting has a specific purpose and is lighting something in particular rather than just a patch of floor. Would it make sense to have it over the island at that point rather than between the island and cabinets? That could also be a track over that part of the island if that is what you like, as long at is is simple enough to work with whatever pendant fittings you choose for the other area. Or it could be a pendant matching the others, even with the different ceiling heights.

Perhaps move the island to the left, so the distance between island and tall units on the left side is about 100 cm and then put something like this over it? You could possibly do that too without moving the island:

In addition to your other post (https://www.houzz.co.uk/discussions/5762468/built-in-oven-and-hob-type-recommendations-also-island-length-for-hon#24431315) here's my idea. Ignore the roofline as much as possible. Place the boiler in a cabinet with a height that ends where the upper cabinets start. Tall cabinets with fridge freezer and oven are against the other wall, together with a 'coffee niche'. Cabinet with washing machine the same height as the boilet cabinet, assuming you don't have a dryer.

Agree with the above. For your pattern / feature tile to stand out more, the other tile should be extremely simple / plain. The colour of the chevron tile isn't very clear, if it is a grey, it may be worth going for a pale grey grout (similar to mapei ultracolor moon white or silver grey), so it can be used all round with chevron as well as the plain white tiles or alternatively, going for a complete contrast and matching the grout to the tiles they're going with. Hope this helps.