I thought the version that people heard of that speech was re-recorded by Churchill years later (frankly he sounded sloshed on it), because they didn't record the Parliament speeches.
Might be. It would have had to have been done either while he was still in power before being voted out in 1944, and before he got paralyzed after his reelection in 1953. It would make sense that it was re-recorded for either the 1944 election season, or the 1953, sort of as a campaign ad before such things existed. Even at the time he made the actual speech, he might have been sloshed. He drank while he worked, and worked while he drank. He must have been sober when he painted.