If you're unsure about pubworking, give The Harlequin in Clerkenwell a go. It's tucked away just enough to be quiet in the daytime and fairly quiet, to be honest, in the early evening too. It's a bit small, but you're very likely to get a sofa seat and here's a little tip: power socket is just behind the sofa! There's a coffee machine too, if you don't fancy a speciality ale and cheese sandwiches on the go. Free wifi, of course - and staff will watch your laptop when you pop to the loo.