A friend of mine installed prefab along her balcony but they ran the length of the house wall, so we're pretty much protected from weather. She had screens installed at either end. Where you see the BBQ and cabinets in your photo, she just had a free standing BBQ. Her cabinets even housed her washing machine, bar fridge and dish drawer. Looked fabulous in white with her timber floor.

Thanks Guinness, the room feels beautiful

If you don't want to settle for either colour shade (dark or light) you can always do a mix: frame of your storage light and have the inside of the shelves is dark or the other way round to match your existing furniture. You could even go and make it a great feature wall. Maybe some the images below will give some inspiration. Another option is to "frame" the fire place area by putting some fire safe material behind and under (maybe in the exact height of your black sideboard on the left wall). Storage could be mounted to upper half of the wall. I'd probably try to leave the storage half "open" since the fireplace is kind of freestanding.

Personally I don't store our clothes to be washed in a few days, and our dishes are just as important to our family health, so dishes get washed and or at least rinsed, is what you get up front.. Guests are welcome to use the dishwashe,r we can easily connect it, so far no problems for them either. I wash, sometimes they dry their choice.Everyone is different I love that.