I'm with you on this one, Shortround; the Battle was originally designed to specification P.27/32, which was for a single engine day bomber Hart/Hind replacement (the production order for the Battle was P.23/35), the 'P' in Air Ministry specs stood for Medium Bomber; it only became a light bomber after reclassification with the appearance of the heavies. Here's a quote from afforementioned H.A.Taylor;
"Designed to replace and improve upon the Hawker Hart and Hind two-seat biplane day bombers, and as a comparative back-up for the B.9/32 [Heavy Bomber - both types were later reclassified as Medium Bombers] aircraft (Handley Page Hampden and Vickers Wellington), the Battle met the specification with an adequate margin - but it lacked speed and defensive armament necessary to survive attacks even by the monoplane fighters of its own design era."
"Designed to replace and improve upon the Hawker Hart and Hind two-seat biplane day bombers, and as a comparative back-up for the B.9/32 [Heavy Bomber - both types were later reclassified as Medium Bombers] aircraft (Handley Page Hampden and Vickers Wellington), the Battle met the specification with an adequate margin - but it lacked speed and defensive armament necessary to survive attacks even by the monoplane fighters of its own design era."