Help me choose a floor tile for new kitchen!

[Aiying]

Hi everyone, I'm in the nightmarish throes of my first ever house renovation (gutting and rebuilding) and hoping to tap the collective wisdom of Mumsnet for advice. Finally decided on a handle-less gloss white kitchen with a white (with grey flecks) quartz worktop. (Aim is contemporary but not easily-dated hopefully). Kitchen/diner is north-facing, about 4m long by 6m wide, and will have 3m anthracite grey aluminium bifolding doors on one side opening out onto the garden. Thinking of getting a glass splashback (neutral grey-green 'glass' colour if that makes sense) ; underfloor heating and porcelain tiles for the floor. Question is what colour floor tiles and wall paint?! Was thinking glossy very light grey tiles...like here: www.tonsoftiles.co.uk/highly-polished-grey-porcelain-tiles-60x60cm-p-89.html#.UfkuWroniEE

Will this look too close to white/be impractical? Would dark grey or matt tiles be better? Would you go for rectangular (60x30) or square (60x60) tiles? Ideally want the same colour for the patio as well - can I use porcelain tiles for outdoors too if they are anti-slip? Planning to have red lamp/dining chairs/accessories to brighten things up, but totally lost about the floor tile colour. Would white walls be too 'hospital-like'? Any opinions/suggestions gratefully received. Thanks!

hi Aying !
its a lovely idea to have the same flooring inside and outside - especially when you throw the doors open for a party ! I have used internal (6mm thick) and external (13mm thick) travertine before - the transition was smooth and worked beautifully ... travertine is too cream based for your colour scheme though ... you could try Portland stone ? it has a slight purple hue (sounds worse than it looks - its not noticeably purple - just a warmer version of grey ) but it works well with greys and whites and warms the room up with out dominating !
the trick is to make sure you have them at the same level - but with a slight camber to encourage the rain to drain away from the doors - and to have proper indoor and outdoor grades - not too shiny (slippery in rain) Fired Earth do a paint called Charlestone grey that works well with white cabinets (and white skirtings/windows) - makes them stand out beautifully - and as a change - if you can have a white wall where the folding doors are as a balance for the grey doors there !
sorry - that turned into a' war and peace' length answer !!! tee hee !!

No idea if they can be used outside as well. I think they are lovely, go for the squares.

Ooh, thanks theWookiesWife and RoseFlowerFairy for your helpful comments! I do realize this is such a trivial 'first world' conundrum to have. theWookiesWife - I shall look into Portland stone (never heard of it so thanks for the suggestion). Where did you get your travertine from - are you anywhere near London by any chance? Did you have them both with matt finish or did you have glossy inside? Also shall look into Fired Earth, thanks for the paint suggestion too - had never heard of the brand until I found MN.
It's a bit tricky with grey because I want to try and avoid that 'concrete slab' look in the garden iyswim. Hopefully Portland stone doesn't look like that.
A friend was suggesting that if I can't get exactly the same tile colour inside and out that I should just astroturf the whole garden instead What do you think?
Anyone else have any advice?
Thanks again !

No to astroturf. Horrid.

I second no to astroturf.

Gloss tiles, nicer to look at, though harder work.