[Stuart]

I think you’re right. The flatter looking cake logo from the first version of the endcap also appears at the start of the Central version of the ITV 1989 generic ident.

youtu.be 

I would imagine it was part of the 1989 presentation package provided by English Markell Pockett.

Looking back in hindsight now at those 1989 Generic ITV idents, they were quite visionary in concept for their time - trying to merge regional identities with a national brand.

Rather classy in a away. Just before their time, really.