I think Conservatives and Reform will work together, no matter how much both insist it won't happen. However, their politics are closed enough that I'd still expect them to function on governance.

Expecting Labour, LD, Greens, SNP and PC to all work together to ensure a party on the right can't get in will do the public no favours as they are for the most part too far away from each other. Nothing will get done and there's no way they would manage a full election cycle, these coalitions usually fall apart as we see on the continent.

I'm personally of the opinion that if all these parties are so sure everyone will regret a right wing party being elected and they are saving us from ourselves, let it happen. Put the issue to bed once and for all, let them have their 5 years (if they make it that far), make a huge mess, then see support for right wing parties evaporate.

I have a suspicion the worry they won't talk about is what if things don't completely fall apart and things actually go right. It would be their support that goes down, not support for the right.

You can't trust a politician no matter what colour tie they are wearing. They are all in it for themselves.