We have been before and are looking for suggestions on more to see.
In the past we have visited:
Tower (Beefeater guide, Crown Jewels and all the rest)
Westminster Abbey (Verger tour was excellent)
British Museum (may go again)
St. Paul's (even climbed to the top)
Somerset House (mostly for the Courtauld)
The National Gallery
Also saw some theater (already planning on that again)
This time a day trip (or two) to Hampton Court and Kew are already on the "list." The above might also give a sense of the sorts of things we enjoy.
We are staying in Fitzrovia for six nights (AirBnB between BT Tower and Fitzroy Square), if that alters your suggestions.
So . . . without further ado . . . please share your thoughts!