I'm having a bit of a dilemma on the door colour. I'm probably going to opt for Farrow and Ball Railings which is a dark grey/midnight blue (very similar to DeVOL's pantry blue). Everything else (walls, worktop, Carrara marble splashback) will be white to ensure that the space isn't too dark. The trouble is that Railings can sometimes be a bit too blue depending on the light. I feel a bit nervous about ordering something I've never seen but the kitchens on Shaker Doors Instagram page do look very good.
Re hardware, we're opting for Armac Martin cup handles, knobs and square catches (from their Cotswold collection). We're also having an antique copper finish which is beautiful and will contrast really well with the darkness of the units. Trouble is the price - £90 (yes, that's nine - zero) for one of the catches. That said, the handles and knobs are more reasonable and so we'll limit the catches to about four. Also we're saving many, many thousands by not having a DeVOL kitchen (not that we could afford it anyway, sadly!) and so I think it's worth the splurge given the units/doors are only £9-10k.
As it's a new extension we've opted for a polished concrete floor which has been poured and now drying. The company (The Concrete Flooring Contractors) are coming back when it's dry to polish and treat it and I can't wait! They've been amazing so far and the floors on their website looks gorgeous. It's expensive compared to tiles (£140 per sqm) but definitely worth it!
Thanks for the recommendation on the worktop supplier, Goingslowly! Ikea have been ok so far it's mainly been us doing the design and we haven't ordered yet. Will let you know how that goes!
Very good point about the units, Barbie! The cost of the hardware means we'll keep them forever 
but we'll definitely paint them when the colour dates or gets ruined by two young children.