So I've just received the email notification from loop today.
The "legacy" version of loop is being switched off on the 19th of December and while they'll send out one of their new electricity monitors for free to existing customers that means no gas monitoring.
(Also I've looked at the new app which has been compatible with the legacy electricity monitor for a while, and it's not very good and doesn't give me the detailed graphs of the old system)
One month's notice to look for something else isn't great in my opinion! Hopefully there is a way to download my historical usage data before it is switched off...
So I take it from the above that nobody has really found a good alternative yet ?