Hello, Gojo.
If you're still working on that TV station sandbox, I've recently been finding some sources that can be cited for the UK broadcast dates of Godzilla/Toho films. Some are on Branaghan's Unknown Culture while I've found others on this great site called The Television & Radio Database; they have a whole section dedicated to films that aired on Channel 4. I've included some of the dates on the UK release sections but I also think they may be worth including on your sandbox, especially since a whole lot of ITV's regional channels aired King Kong vs. Godzilla. It'd be wonderful to see it all archived.