La Trouvaille is closed so I need somewhere else to take my partner for her birthday.
It should be in central London, not too formal/stuffy (we aren't fans of the much-cited napkin test) and in the GBP 35-75 range.
The difficulty is that we have a birthday meal rule which states that the restaurant must be new to at least the recipient. Whilst I don't expect you to know where my better half has dined (and indeed would be somewhat perturbed if you did), this gives I think a frisson to the challenge - your suggestions should not be too "obvious".
Over to you...