Hello again,
Thanks all for identifying this set as a 1963 Defiant A55 and its PP11 2x 4.5v battery. I have now got a copy of Trader sheet 1607 for the set and as PP11 batteries are long gone I shall convert it for PP9 use as described by Bill.
It's come up really nice, and it's not unlike a Perdio Fanfare in construction and no doubt will soon appear in Success Stories.
Howard