Not strictly a café, but a cocktail bar run by our very own Tristan!
Purl
I had the chance to check it out last week in the fair company of the lovely Anette and we ordered one of Tristan's not alcoholic espresso based drinks, which had to be seen to be believed (think espresso, white chocolate and liquid nitrogen!). It's a great space and the bar staff are a fun bunch.
So if you fancy a coffee based drink once all the usual cafés have closed at 6/7pm, it's definitely worth checking out!