First of all, I'd do something for the body: a gentle mid-morning run around Hyde Park with preferably no interference from the speakers at Speakers' Corner and lots of interaction with adorable over-excited, waggy-tailed dogs. These dogs do not leave poo on the park paths and do not chase to bite; they only chase in a friendly, playful fashion. And I find exactly the right volume level for my mp3 player so that I'm not oblivious to everything around me - including imminent danger - but at the same time, I've blocked out traffic noise and aeroplanes going over head.
After a few laps, I would head back home for a shower and change of clothes before catching a black cab to the Phoenix restaurant for the best dim sum in Zone 1, noodles and noisy gossip with family.
I would then abandon the family and the part of the day spent taking care of the body and move on to fulfilling the mind and soul. Next on the "to do" list would be to collect some friends to do some squirrel fishing in St James Park and to feed the ducks. The weather would be warm and sunny enough to lie around on the grass with the Sunday papers. There should a game or two of frisbee with more adorable, over-excited waggy tailed dogs.
Once the novelty of the park wears off, we pile into the ICA bar to drink gin and tonics over a game of Cluedo followed by Monopoly. Once I have won all the games (and this is my perfect Sunday so my "deduction by probability" theory for Cluedo WILL work) we part ways and I get another cab across town to an intimate and cosy dinner at Kazan with my fiance. Five or six courses later, we saunter along to the Boisdale for whisky nightcaps and some live jazz then... we'd wander back to our fabulous riverside penthouse home to watch Seinfeld DVDs, cuddled together on the sofa under a big fluffy blanket.
My perfect Sunday in London would not involve it turning into Monday.