Norwich had Machin definitive (MA14) and Working Sails stamps:
It is likely that other Machin versions will exist - MA13, MA12 etc. Indeed MA13 stock was in the Royal Mail machine at Crewe Delivery Office.
But the surprise - and perhaps disappointment for collectors and dealers - was that the location identifier, introduced only with the new machines on 2 February, had been removed. Thanks to Stuart and Alf for telling me about Crewe and Bradford North respectively.
Mike reports that Mount Pleasant, Camden, Baker Street, Great Portland Street & Trafalgar Square offices in London all have Machin stamps only.
UPDATE 31 March
Thanks also to Stuart for pictures of Crewe (M002) and Bradford North (M003) stamps produced yesterday with no name. These are both MA13.