Framed corrugated iron shutters left natural would be my preference, colour might be a bit 'try hard' and natural will sit in the environment more easily. Could even make barn doors with it if you prefer that look. The actual barn door fittings are the pricey bits I believe. Our cyclone was made of corrugated iron (by pro shelter builders) and it never ever budged (loud though) so a bit of coastal? wind won't worry it. You don't have much wind going by photo's, all trees seem to be growing upright so a regular build will be fine.

Stone Pros, it looks amazing Cons: its expensive and requires a stone mason. Mirrored/Glass Pros: Modern and easy to clean Cons: Requires a specialist installer Brick Pros: Great for industrial look Cons: Hard to clean

By your pictures you have chosen lounge settings. Is this your preference for this area, or would you be using space for actual dining and entertaining. I find that low lounges like the ones shown are not ideal for eating meals. You end up with a plate on your lap.

If he's on a tight budget , why not get a dozen Subway tiles in a colour he likes , and lay them horizontally around that kick up ? Cheap as chips , as colourful as you want , easy for a DIYer . And lets face it , if you are getting splashes above that level , you are probably doing something wrong -- 100mm should catch 90-odd % of the splatters . You are probably going to strike problems with the power points getting food and fat and steam in them too . And talking about colour , maybe get a jug and toaster in the same or complimentary colours -- we know England is grey , but that's just being ridiculous haha !