I'm going from home to Narita to London when the weather will be very different in the two places.

I'd like to pack a separate bag for London and leave it at Narita. Are there left luggage lockers convenient to leave when I land and reclaim from baggage claim and retrive for checking to London when I leave?

And I can check two bags and carry-on one plus a personal item, right? It's the weight not the quantity for the checked bags, yes.

Sylvia