Recently, my lovely husband and I took advantage of the Evening Standard's Dine offer (now closed) and visited Avenue. I picked it mostly because it is close to where I work (Victoria) and I have yet to really find a restaurant that I love near work which I feel is a bit of a shame.
As regular readers will know, I am (greedily) mostly all about the food in a restaurant. If a restaurant serves food that I love, as long as there aren't rodents visible and and the staff don't spit in my face, I will pretty much be happy to go back there.
That said, the service at Avenue was so good that even I noticed! The waitstaff had it pitched absolutely perfectly - they were always prompt, they anticipated when you'd want more water, when you'd want to order dessert, etc, etc. And they had ridiculously good attention to detail - e.g. we were sat at a long row of tables for two that were fairly close together and they seated groups as far as possible spaced out along the row, to avoid you having to be unnecessarily close to another party. The waiter also won my heart by filling my hankering for ginger tea after the meal by getting the bar staff to add some chopped fresh ginger to some green tea.
The attention to detail carried through to the food too - for example, my pumpkin risotto was elevated from standard vegetarian risotto fare by the toasted hazelnuts on top that gave it a much more interesting texture.
The only complaint from me was that the puddings (very nice - banana sticky toffee puddings) weren't really anywhere near hot when they appeared, which was a bit of a pity.
I think it may be just a touch too expensive (£15-£20 for a main course) for me to want to go there regularly for the a la carte menu but I think I could definitely be tempted back for the set menu or the pre/post theatre deals that they have.