The Loungers have had a couple of options that have been veganisable for a while but they now have a dedicated vegan menu. It's to be honest a little bland, and the options are generally veggie options from their main menu with the dairy taken out and nothing to replace it. In some cases, such as tapas you'll get a sweet chilli sauce instead of the standard dairy dip.
I have had issues there though in that they forget to use soya milk in coffee and will give you butter and non dairy dips when you ask for them to not be provided.
They do how ever have a couple of vegan deserts which sound nice, but I have not had chance to try yet!
Cons: Chef's Fail to provide vegan options, Waiting times when busy