OS MasterMap® Address Layer 2 builds on the success of Ordnance Survey's current addressing products by offering significant enhancements such as geographic alternatives, building names aliases, Welsh alternatives and two new datasets - Objects without postal addresses (OWPAs) and Multi-occupation without postal addresses (MOWPAs). All addresses contain up to four classifications, together with Ordnance Survey's unique identifier - the TOID.
If you're only looking for addresses covered by a postal address then Address Layer will probably suffice, however if you want all addresses then Address Layer 2 is the product for you. If you require any additional information, please don't hesitate to contact us!