Seriously, what does she like? Is she a shopper, or a birdwatcher, or walker let's see the sights? I would recommend the London walks if you're there. They have fabulous walks in different neighborhoods. Me and He took the Jack the Ripper Walk in the evening, it was fabulous, scary and informative and got me into his arms (my boyfriend not the Ripper).
Well, that depends what you like doing. If you're an outdoor type, then Longleat is worth a visit for the animal/safari park, and they have the massive Longleat maze which is fantastic. Brighton is pretty cool if you want to go the coast.
