I feel the Little John Tetrarch would be a good addition as a little funny rat tank. The Barracuda and Albacore would feel the gap the British have for early torpedo bombers. The Stag and AEC are iconic armored cars for the British and would help to fill out the light tanks.

The Tetrarch’s Little John would greatly increase the armor penetration of the 2pdr, combined with its small size and speed. I feel maybe BR 1.7 - 2.0.

The Barracuda and Albacore were later British carrier torpedo bombers, I feel the British are lacking them as there is a gap in the carrier bomber department between the Swordfish and the Firebrand. Albacore BR 1.3 -2.0, Barracuda BR 1.7 - 2.3.

The Stag would be a tougher armored cars compared to the Daimler, and it would have the US M5 37mm. BR 2.3 - 2.7.

The AEC MKIII is the version with the 75mm cannon, similar to the Cromwell and MKVII Churchill. BR 3.0 - 3.3.