I understand why people make the comparison to Cox/Amess, but it seems to be two different issues - consequence and regularity. Being murdered and actually dying is obviously a very severe consequence and both of their deaths were tragic. However they were also both essentially random, as I understand it; neither of them were particularly high-profile or widely-despised or anything like that. It wasn't like they had been exposed to an escalating chain of threats and attacks for years before they were killed. They had no reason to think, before they were killed, that they specifically would need extra security.
Again whatever you think of Nigel Farage - he is widely despised and it wouldn't be particularly surprising if someone did try to kill him.
Please don't interpret this post as "Nigel is worse off than poor Jo who actually died", my substantive point is that Farage has information in advance that he (and perhaps other Reform politicians) is at risk and he's entitled to act upon it, which is different from the situations of Jo Cox and David Amess. Please also don't interpret this post as calling for Farage to be killed!