Joe, the British Library is a two-minute walk from all three of the rail termini serving "the north" - ie Kings Cross, St Pancras and Euston.

Why do you need to know this? Well if you get a reader's pass (usually a ten-minute wait; tell them you're researching something) , the music and rare books libraries are phenomenal resources. More important, the building has extensive and well-appointed "facilities" - including free luggage lockers. If you've bought loads of songbooks and need a really huge locker, go to the desk and they'll give you a key; otherwise help yourself to one of normal proportions, for which you'll need a (returnable) deposit coin. (20p or 1GBP I think.)

I should be there to say hello, either Wednesday or Thursday.

On a couple of occasions they let me leave stuff overnight, but I did ask first (I've got a reader's pass.)

BTW there's a curious catholic church in Ogle St (St Charles Borromeo) if you get the time - still Neocatechumenate a year or two ago,in the face of much hostility from parts of the UK hierarchy. (Huge walk-in font etc.) St Ethelreda's (Ely Place) is the oldest, and survived the reformation because it was the private chapel of the Spanish ambassador.