Inside these modest containers are lunches designed by a chef who has worked in Michelin-starred kitchens and whose blown-up image graces the wall right over there. What's more, profits are all going to charity, folks. Am I imagining it or is there a genuine Mr Feelgood feel to this place today as office workers in summer clothes dot in and out?
Behind us there's a big notice on the board asking if we want to leave suspended coffees or food for a homeless person to pick up and have later. There's also a photo of one of the workers - Pete from Edinburgh, since you ask - on the wall, and a little bit of blurb on the all-over cheffiness of Mr Michelin star himself, Mike Mathieson, but that's almost it in terms of charity hard sell.
Close one eye and this could easily be a Pret or any of the other lunchtime sandwich chains, with its light, airy, clean and crisp layout. In fact I'm wondering how many of the customers hustling in and out are actually even aware this is a totally not-for-profit organisation and that they are committing a charitable act for which they will surely be rewarded in this life or the next.
We still haven't opened our lunches yet but Leo - who can frankly come over a little saintly sometimes - leans towards me and stage whispers that this is one of those places you really want to do well.
Crikey. Normally I would recoil at such raw sentimentality, but I do know where he is coming from. In fact, probably better than all the profits going to charity - who doesn't get hit with the occasional wave of charity fatigue these days? - is that Social Bite trains and employs former homeless people. As the website video says, obtaining work opens doors to so many good things that most of us take for granted. That's my lunchtime sermon over, because while we were waiting for the hot stuff to be brought we bought a Super Green hot wrap from the counter.
Now, yes, I can hear a loud groan from the back. On paper this promises grim eatings on account of it not only being for-charity food but a - shriek - vegetarian sandwich to boot. Once upon a time this deadly combo would have sent a quivering nation bolting for their Vesta curries. Fear not. Things have moved on dramatically and the onions, spinach, leek and green beans have not been left to their own wholesome devices but rather jazzed up with good old full-fat cheddar and a major hit of lemon mayo which actually, genuinely, gives it a great flavour. Is this the Michelin input? It's good, anyway.
The hot food? I wish you could have been here as Leo and I opened the lids of our Mexican chicken and Hong Kong pork. For a moment there was an audible double groan of disappointment because, frankly, what with these polystyrene food compartments and fill-the-slots presentation, it just doesn't look appetising. But then, like in all the good movies, we taste the food and it's not only packed with spices but there's cumin and butter beans in the Mexican chicken and sesame and ginger coursing through the Hong Kong pork. Hurrah. Both dishes are not only good but completely finished.
Of course, there have been other charity-run cafes and takeaways in town and there probably still are, but mainly they tend to be slightly off the beaten track and operate in a low key and unambitious way food-wise that doesn't bring them into the orbit of the aggressive and highly professional sandwich chains. This is different.
The best thing Social Bite can do is draw in customers who have no idea about its charitable status and who come simply because it's good. And it looks like they do.