Hi, Jane. Welcome to the community!

Step one, here, is to go back to the risk assessment. This is in order to ask yourself an important question, which is whether these measures are, in fact, a proportionate mitigation for the actual risk. Is the mobile phone reception still as patchy as it was when this arrangement was first put into place? If so, how far would they have to walk before they had adequate reception to reach emergency services? Are the roads actually dangerous? What other means are available to staff that get into difficulty? Can you equip staff with hi-vis and other equipment that will mitigate any element of the risk?

If you can determine that, in fact, this is no longer a reasonable mitigation given the assessed severity of the risk and other mitigation measures that are or could be in place, then the whole problem can largely go away: those managers that don't want to do it don't have to. No one needs to do a check-in!

If, on the other hand, having revisited the risk assessment, you determine that there is still a risk that needs to be mitigated and that a check-in is a proportionate and effective measure for mitigation, now those relevant managers need to be told as such.

Refusing to follow a reasonable instruction - especially one that relates to mitigation to a properly assessed health and safety risk - isn't just misconduct; it's potential gross misconduct. Perhaps, when cast in that light with the underpinning of a fully-reviewed and updated risk assessment, they will re-thing to what extent they are prepared to die on this hill.

In reply to Robey:

Nothing too helpful to add I'm afraid just the observation that Robey and I had very different first thoughts about potential risk that might be encountered. Robey felt that hi-vis vests and not too far to walk might mitigate the risk (clearly road-related), mine was that if I was alone walking on rural roads at night, I wouldn't feel much comforted by a hi-vis! Just another of our daily reminders that life is different for women and for men...

However, yep, your RA is key. And if I was said woman working on my own I would hope my manager would care a little...

In reply to Annabel:

I must admit when I read the OP I was slightly shocked. I don't know how often Line Manager or Senior Leader is expected to take the check in, but it seems very selfish to refuse to do so. Is it a contractual term?

Perhaps my view is slightly different being ex-Forces and therefore used to being Orderly Officer or Casualty Notification Officer on a rota, or working now in education where SLT and Safeguarding Leads have times on call. However unless the duty falls nightly year round it really doesn't seem unreasonable!