RAH (I just like abbreviating it 'cos it's funny: RAH. RAH!), then I highly suggest you drop in to one of my new-found favorites (okay, okay, I can't take credit - John found it): Tombo, an incredibly charming Japanese cafe and deli located a stone's throw from South Kensington station.
A breath of fresh air from the ubiquitous "Japanese" chains, Tombo is the perfect place to go when you're looking for something between pre-packed sushi and greasy udon pots - something homemade and nourishing, such as the bento box above, which includes your choice of main (chicken, salmon or tofu), multigrain rice (which feels a lot better in your tummy than the usual white rice) and a choice of three sides (I had the mooli and carrot salad, seaweed and edamame bean salad and carrot and radish salad). The chicken is succulent and tender and the sauce isn't too sweet, which is always a common complaint of mine when selecting chicken donburi or bento boxes.
They also have a delicious selection of Japanese desserts (oh how I miss mochi and iced mochi!) and teas which I am dying to try the next time I break from a shopping trip.
The smart decor and friendly staff also add to the enjoyable dining experience; the white walls are decorated by whimsical paintings by the magnificent Nastko Seki, which, accompanied by the comfort food makes you feel like you're dining in a friend's chic living room, rather than a West London cafe.
If you plan on going, be prepared to wait at least 5-10 minutes during peak hours (lunchtime, for example) as it's clearly a popular place - but totally worth the wait.