This is a reply for both @Phi & @hmowilliams (and anyone else who wants to contribute to this thread):
Hi, firstly, I am the original poster charityjf, I just started a new account because I wanted a different user name. Also, sorry for the delay replying, I had some other stuff on the last few days.
Anyway, thank-you both so much for your ideas! It’s great that I have a few options to try; this makes me feel really optimistic that I’ll find something that works and that would be seriously LIFE CHANGING! 
.
Re: the Runkeeper option:
I have done some research on this, because as you say, a benefit of that over IFTTT location tracking is that it can be used anywhere. BUT, it seems a problem with this is that I could input manual data, either into Runkeeper (see first link below) or into Beeminder (see second link below), and that makes it not at all weaselproof, which I need it to be.
https://forum.beeminder.com/t/runkeeper-disable-manual-logging-entries
.
Re: the IFTTT location tracking option:
I would love a walkthrough for how to do this, yes please! That would be really kind of you.
Does anyone have any thoughts on whether this could be made to work if I go away also? Of course I could change the location I need to leave, but only upto a week beforehand, & I sometimes go away with less than a week’s planning. Would IFTTT allow me to pick two locations, and the rule is that I need to NOT be in EITHER of them by a certain time in the morning? That way I can set it up so I’m not allowed to be at home, OR at my sister’s house in London where I sometimes stay. If it could do that, this may then be a PERFECT solution. If I can’t enable that, I can still use this solution, and either have some ‘days off’ each week that I make sure I save for if I go away, or sort something out with support as you said earlier @phi.
Sorry this is such a long and involved thread, thank-you SO much if you read this far & are still giving your time to helping me sort this out. I really do appreciate it HUGELY.