We called at Dil Se having seen it recommended here. We went in at 4pm to check the restaurant could accommodate the 2 food allergies in our group (dairy, and onions) and were told that this would be fine, everything would be cooked to order and these requests could be accommodated.
Unfortunately, when we came back later, we were told that they could not accommodate a request for dishes to be non-dairy, as ALL THE FOOD IS COOKED IN A MIXTURE OF GHEE, BUTTER AND OIL! On insisting that we were told that this was fine, they eventually agreed to cook my food in plain oil, but it took a great deal of persuasion.
Unfortunately, the request for no onions, which was apparently possible, was completely ignored by the kitchen.
On paying the bill (which contained no reductions, as it should have, given the poor service) I was specifically singled out and called "difficult" by the waiter.
I have never been treated so badly by a restaurant. I frequently eat Indian food, both at home and in restaurants around the country, and it is usually simple to accommodate a request for food to be cooked in oil (all I wanted was a chickpea curry and plain rice!).
I will never go back to Dil Se, and I would encourage anyone with an allergy or intolerance to avoid it. It is clearly not suitable for vegans at all.
Generally, the food was bland, the ingredients were not fresh and the food was not at all spicy.
Cons: Terrible service/rude staff, Inability to accomodate vegans, Completely ignored our allergies