Thank you for ideas @Sian: yes, that could be a choice, since we sure need the space. I'm just afraid of loosing the space that sometimes is valuable when family/guests comes over and you want to socialise while cooking. @wuff: Oh, you mean a built in nook? I also thought of it, but since we just renovated the bathroom and laundry, I'm trying to pause any (costy) projects and rather focus on plain furnitures.

I did a chuckle at the time. I know those moments! I also know people will ask you to post a whole house plan, which way north is, how many people in house etc. A complete house plan would give you much more informed answers.

If you search DIY banquette on Pintrest you’ll see instructions and measurements. Most are in inches but you can convert them. Could you measure the seat height of the chairs you are using with the table (you need the table first) subtract the cushion height and that will give you the bench height. It does depend on the height and weight of those that will be using it the most, to get the best fit.

You would have to ensure that there's suitable insulation in the Nib and western walls in the extension the cavity brick in the original part of the building should be OK remember vergola its an opening pergola you would be advised to get a quote but this would certainly work and look better it doesn't have to cover the whole deck