I'm up to the point on the Network DVDs where the Cadbury's sponsorship had started, and the abrupt cuts on the part one/two captions and to the endcap make it quite obvious the sponsorship bumpers are on the master tapes themselves and they've been cut out. I think these days they're played in separately?
I’m pretty sure they’ve been played in live since almost the start. The episode on 31st August 1997 (the day of Diana’s death) went out without sponsors, and looked quite clean - although Granada/ITV may have had access to a clean copy to play out that day.
Emmerdale used to have different sponsors in different ITV regions so they were always played in live, as far as I know. Julian Simmons made reference in a behind-the-scenes clip to the fact UTV used to play the Emmerdale sponsor stings out locally.
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