Have a look at the permeable paving products. The stones look good too, can be a bit difficult to keep them in place though as they can spread around.

"Tribbletrouble' has given you a great link into similar situations.There are a few there that look similar to your side passage. If it's a major thoroughfare for bins and wheelbarrows be aware that stepping stones look great but are awkward to traverse if not laid well. Fewer larger ones would be better than lots of smaller ones. If using pebbles, put down a firm base, eg roadbase, with a thin topping (25mmm) of pebbles. If the layer of pebbles is too deep they are awkward to walk over and drag bins through etc. I don't know where you live but your local nursery will be able to guide you with plant selection for your area and your aspect. Best wishes.

kitchen to south any day of the week....I'd also go further to suggest that possibly the building could have been designed to have the kitchen hard to the south boundary that would have opened up more north light opportunity and better use of the (unusable) side space behind the kitchen. You'd still need a light court for the bedrooms etc...& possibly by doing this the future pool could have been flipped and oriented more to the north/west corner and the net effect would be having more options/flexibility for the outside space, & also possibly alfresco area located on the north which is always better than to the west, so alternatively an extension that is more streamlined in design, following the line of the existing building rather than kicking out, I can see immediately that this type of design strategy would bring some arguably clear benefits on a number of levels .....not sure how far down the track you are (looks like still in concept/sketch design stage) may I add that it's always cheaper to consider re-design on paper rather than regretting less than ideal outcomes after they're built...... anyway food for thought........always consider the options and maintain an open mind...it's always ALL in the design Best of luck Cheer PD :)

I wonder how much time you might have to spend cleaning the roof behind the parapet, perhaps the rain will take care of that, leaves?. If you were going to use these spaces as terrace you would need to adjust the height of the parapet or add a railing, if not the height of the parapet could be reduced