I have a 7+ hr layover between arriving at LHR and connecting at LGW. I would like to do a little sightseeing in downtown London. Are there any stations that allow luggage storage (e.g. Victoria Station)? I am planning to take the tube into the city from LHR and then the Gatwick Express from Victoria station. I will not be flying BA out of LGW but a BA codeshare so will need to check-in physically at LGW. I don't know if they still have a BA check-in desk at Victoria, though I remember seeing one when I last visited 15 years ago.