Three Brand ZTE MC801A B12 Update

[Skeezer]

I have the Three branded MC801A 5G router from Three and since this morning I can no longer force 5G via band selection here: 192.168.0.1/index.html#debug_page
I had speeds of 300MB+ on 5G, I'm now on 4G+ with 16MB. I call Three and their is nothing they can do. i have tried ZManager and that crashed when selecting a band. I also tried a method in chrome that I found on Youtube however that gives a 403 Forbiddon access denied.
It's poor of Three/ZTE to update their router and take this option away.

Will their be a fix?

Edit: Keeps bouncing between the two every 30 minutes
4G+ signal is -69
5G signal is -103

Just got off the phone to Three Technical and they said works on my local masts are going on in my area WA7 and that's why the option to force 5G is not showing. I don't think this makes any sense as it seems everyone has lost that option. I explained to them these options disappeared after the update to B12 but said the above. They said once works is complete, the option will automatically appear 

[StephR]

Hey Skeezer, 

I've asked for more insight on this topic for you, I'll let you know when I hear back on that. In the meantime, did the technical team advise when those mast works are due to be completed?

[StephR]

Hi again Skeezer,

This isn't something Three has specifically changed, but the option has likely been removed as part of regular security updates. Debug pages wouldn't normally be accessible for customers.

Having a general look over the Runcorn area, it does look like we're carrying out some mast works there. Keep an eye on that via our network status checker - hopefully it won't be too long before things are running at full speed again.