For me...I'd keep the deck the colour it is, may give it a refresh if necessary and go hunting for outside bentwood firniture, you know that curly bamboo kind, it never dates and is elegant and above all comfortable...where many outdoor settings may look good but are not inviting. If the space were mine...and if it had shelter from the elements, or if you didn't mind some of those outdoor firniture protector covers for inclement weather ( when you may as well bring the furniture in...whatever it is..) .I'd also condsider going on the hunt for some lovely old colonial-looking wicker items painted brilliant white, it always makes a statement, always looks classy and is always gentle on the posterior! If you can find the genuine article often you will discover that the seats are made of entwined dried grasses and palm leaves. I'd also go looking at some of those plant/cafe' places...that sell plants, fountains, as well as up-market snacks and are often furnished with wicker...no harm in asking where they bought it...they may even sell it. Its a cosy little space...I'd just have come large comfy outdoor chairs and maybe little side tables. Think of fancy English ladies sitting out of doors watching a cricket match on the manor lawn and sipping drinks...that's the scenario I see there. Maybe even one of thos old tall plant stands with a large green specimen plant....Most of all....have fun.

Out door gas heater for night time, or a fire pit, music and the usual ingredients good food, good wind, good friends...then nothing can go wrong as good friends won't mind or give you a hand

You could go wider but it depends on what type of dining furniture would want to use and how many you will be catering for. Bench seating tucks underneath and when it is being used you aren't so worried about the other space. You could always turn it around the other way [ perpendicular to the house] so the width is less of an issue as 10 metres is a decent length deck. I think even an extra 30cm would make a difference and not doing it may cost more in regret than the materials. You could go wider in the dining area only but it is a bit hard to judge without seeing the space. Find some furniture you like online and map out a plan for yourself - use newspaper for life size modelling. Good luck

consider professional powder coating..much better finish and good investment for a quality outdoor setting