Oh yes, I made an appointment - thanks crazycatgal! 
Unfortunately where the wall units are now seems to be the best compromise for me - the huge great big fusebox they hide cannot be hidden any other way! So it follows from that, I figure, that they should be 'joined up' at one end with a tall oven unit seeing as I need cupboards at that height anyway - iyswim? YorkshireTea86 If I use a mid-height oven wouldn't I end up looking at the side of the cupboards I have to put in to hide the fusebox?
KeiraKnightleyActsWithHerTeeth - I had considered moving the tall unit to the other end - but it's 60cm deep, and would stick out right in front of the window. It's pretty much wall-to-wall window on that side and it seems a shame/a bit odd to block it maybe?
The tall unit on the other side is the integrated fridge, yes. I considered putting it next to the tall oven unit so the tall units are all on one wall Badweekjustgotworse, but I'm a little bit wary of putting appliances designed to cool things next to appliances designed to heat things. Putting it there would also really limit the 'elbow room' around the hob - and the hob does have to go on that wall because the fan cannot be moved to the other wall; there's nowhere for the extractor tube to go from there really, as that wall backs onto the living room.
Do you think having just a freestanding fridge would make it a bit less oppressive feeling? That's what we have now, and it feels alright to me at the moment. OR, as GreenTulips and suggests I do like the idea of putting the oven unit under the counter - but where would the microwave go? I'm so unimaginative!
We have a baby - I'm hoping that we'll have moved on once she's big enough to go charging about anywhere!
And I'm planning on buying a freestanding Ikea trolley/island for the center of the room - it means we can keep the space flexible when we have lots of family round.
DeepInFrance - ooo that's interesting. Why do you think the drawers hidden in a cupboard are better over the individual ones?
RandomlyGenerated - ah, of course! Brilliant tip, thank you. 