I was thinking about Ceasarstone in Blizzard. Any thoughts?http://www.caesarstoneus.com/products/color/2141/

As you can see it's a work in progress ^_^* On the left part there is a shoe closet with a mirrored door. What I have in mind is something like this in the attached picture but for a seat, not a table. As you can see, the top part can serve as a place to leave keys, post, etc. and the whole thing would rest on the floor so the "seat mechanism" would be in the middle-upper part and when opened, the weight would be distributed among the legs of the chair and the main part so no need for heavy bolting. Although I don't have a problem with that either if there would be a flip-up seat with no floor support integrated in the "closet" part. And by the way this thing is precisely 15cm deep so it would totally fit in my plans :-) Anybody any idea? Have a great day!

That stove can be placed against a flat wall with pipe open so as long as your chimney breast can take the stove pipe I personally think it will be fine. I don’t think it will look wrong if the bench is deeper and if your room is normal sized it will probably be better??

I agree with @Daisy England regarding drainer grooves are not necessary, in fact the amount of fall is so minimal and so little water drains away you might find having the extra worktop space is more useful, there are worktop drainer boards https://www.victorianplumbing.co.uk/reginox-ceramic-belfast-sink-kitchen-drainer you can get instead which may be more practical. Adding drainer grooves to wooden worktops may invalidate the guarentee so check the small print, you have solid surfaces like mistral, minerva which are solid all the through, but they can/do scratch quite easily (es[ecially the black/dark colours), solid laminates worktops but these usually have a black core so if you add drainer grooves you lose the worktop pattern. If budget can stretch quartz/granite would be a preferable option and just put a tea towel down on the worktop to soak up the water.