This is another slightly different style tire pump supplied with early model MGA. This one is known to have come from a December 31, 1958 MGA. The cast baseplate is slightly wider at the square shoulders, and the heavy wire fold-out feet are formed all in one plane.

Addendum 22 September, 2019:
There was this ad page in a period magazine (The Autocar, 18 July 1958) showing what appears to be the same pump labled as "The Aerite" car hand pump, touted as "standard equipment on the MGA".

The AERITE (regd) Car Hand Pump, Standard Equipment on the new M.G.A. Also available from oil garages and through Halfords branches. Price 10.6 Walters & Dobson Ltd, Bailey Street, Sheffield, 1