I don't think it's a niche issue at all
It's not, but in terms is how important it is Polling on the doorstep it's a low priority. The guardian have run a story on this today (I linked to it on the JKR response to Labour MP thread).
The point they make is that the tory voters are more socially conservative and views on this are generally fairly consistent however the Labour Party has a problem because its voters are split on the issue.
This means Labour are keen to bury the topic, whilst the Conservatives want to push it.
I would argue that this isn't going to go away for Labour - we have the Olympics next year and there is likely to be court cases.
Whilst they may hope they can keep a lid on it, wanting to pass law when they win election, the Labour Party has to win an election first... This issue will not appear on a manifesto because its easy pickings for the government to show how out of touch with the public they are.
This is why pressure needs to be kept up.
A pincer movement from the women of the left and the Conservative party will be uncomfortable for Starmer. It needs to be.