The postal address is as follows:

London Studio Centre
42-50 York Way
London N1 9AB
United Kingdom
Tel: (+44) 20 7837 7741
Fax: (+44) 20 7837 3248
reg. charity 803577

Nearest Tube station is King's Cross - York Way runs up the East side of the station.

Here is a map from StreetMaps.co.uk, and a aerial photograph on Google Maps - the Centre is a little south of Wharfedale Road.