... as a combat aircraft, and cancel anything you want for that to happen. In order to remain relevant, it needs to grow in capability - a combination of increased bomb load, more speed, better survivability, suitable for other combat roles. Nice to have will also be another production source, whether in UK or abroad. Make it carrier-borne if you want. Plus points for scenarios where it can play a key role in a crucial battle or campaign.
When you put the two side-by-side, the Battle is roughly comparable to the Nakajima B5N "Kate" torpedo bomber. The Kate can carry a slightly heavier payload, the Battle is a bit faster, but range is about the same. In the case of this AHC, the FAA is permitted to order an all-metal monoplane torpedo bomber, which is just a modification of an RAF light bomber. The Sea Battle features a slightly breathed upon Merlin (and this is really the biggest bottleneck) to make up for the weight increases from carrier gear and the new inward-retracting undercarriage and strengthening to carry a torpedo. While the Sea Battle isn't a frontline aircraft by 1945 anymore, it soldiers on, due to its more powerful and capable replacements not arriving until later. Its docile handling characteristics make it easy to land on a carrier, and many worn examples are used as trainers for the next generation of FAA and Imperial aviators.
If you wanted a full Battlewank, later Marks replace the Merlin with a Griffon, put 4x HS.404 20mm cannon in the wings, reduce the crew from 3 to 1, and replace the long glazing with a teardrop bubble canopy to reduce weight and improve visibility (although this would alter the centre of gravity and require modifications). The Sea Super Battle also gains the capability to mount drop tanks, and its long wings allow rockets to be mounted outboard, so it becomes quite a potent ASW and AShW platform in its day.