Supposedly she was taken on a barge and her floatilla passed under Traitor's Gate and that is where she saw the heads of her two lovers on a spike and was then executed BEFORE Lady Rochford. Why would the writer make such glaring changes in the script and have her executed WITH Lady Rochford? Seems like an unneccessary change to me.
shareThere's a sort of poetic justice to it, don't you think? They were in it together and they went out together.
shareThis series takes a number of liberties with the known historical facts. this is a relatively minor one. I suppose they thought it looked more dramatic that way.
shareThe 'with' Lady Rochford is kind of accurate. They were executed on the same day, in the same spot, it was just the other way around with Catherine being executed first.
I agree with louiseculmer that they likely changed that around for the show because of dramatic reasons.
As for her seeing the heads of Culpeper and Dereham in the tower, it was probably simply cheaper to shoot that scene on an already existing set than it would've been to shoot it outside on a boat. But that's just a guess.
Its not that much a stretch to explain why they did it that way in the show
1. It would have been hard/costly to film a scene on a boat where she sees the heads.
2. Obviously Catherine gets executed last for dramatic purposes
3. Once again probably too costly/pace-slowing to give Lady Rochford a solo execution scene