It's one of the smaller wahacas, and thus the menu if different to the other branches. The vegetarian options can therefor be a bit limited. Because it's on the popular tourist spot that is the southbank, it's usually very busy. So a 20 minute wait is average. But this is still nothing to the hour+ wait expected at Wahaca Soho on a saturday night. The Waterloo branch is larger, has the full menu, and is only a 10 minute walk away.