I have heard of Boosty, but thanks for the info - I'll look into it further into the new year.

I just thought I'd update my old thread, effectively closing it as "SOLVED".

Since around 20th December 2017 onwards, the speeds obtained from my load-balanced ADSL + 4G link have been very respectable - ranging from 10Mbps down & 1Mbps up, more recently to just over 50Mbps down & over 10Mbps up (at times)! Only on 1 day has the speed dropped below 10Mbps down (& then, only to 8Mbps down) - other than that, my 4G connection has fulfilled my ambition as a "DIY USO [Universal Service Obligation] connection", to provide me with a turbo-boost (and backup) to my slow ADSL Max link to boost it to at least 10/1.

I can only assume that, during last autumn, EE were doing work on & upgrading the cell masts in my local area (possibly even provisioning extra ones) - hence the erratic connection quality during that time. Of course customers seem to be kept "in the dark" about work on local cell towers, hence my confusion over the degraded performance. The EE network coverage map now shows "excellent indoor and outdoor" 4G coverage, and also "Double speed 4GEE", for my area, which is a very recent change (used to show as "weak outdoor & no indoor" coverage) - so I assume any work was related to this!

The "LTE Discovery" Android app seemed to indicate a possible new cell tower nearby - so I re-positioned my router in another upstairs window (where there was previously no 4G signal), and this yielded my current average downstream speeds of > 30Mbps (sometimes over 40Mbps or even 50Mbps+), and upstream speeds of consistently over 2Mbps, sometimes over 10Mbps. (e.g. SpeedTest.net result). Much better! And that's still without using my external antenna - which will be installed & tested soon.

Now all I could do with is a large data allowance on SIM-only (EE do 200Gb on Mobile Home Broadband, but only if you use their own router).

Hopefully we'll soon get Fixed Wireless link too in our area (or even maybe FTTC/FTTP one day!). But until then, at least 4G seems a good stop-gap.

Anyway - "Case Closed"

Many thanks for all ideas & advice received in this thread.

Kind regards,

Adam.

One thing that I have learnt in all my time of following the upgrades of the mobile networks to 4G, is that as soon as 4G is available/rolled out to one mast a phone clings to it until thresholds are met when it switches back to legacy (3G/2G), even if 3g is stronger
so you are probably right in saying more users = slower speeds (congestion)
but over time as more masts have been upgraded that problem has gone and now 4G is pretty much everywhere and at full speed, i have noticed in my area that
from around 11-midnight i get 60Mbps+ on my iPhone on EE and i put that down to people going to bed so less congestion, but average speeds are usually 20+ in the day, and uploads are always atleast 3Mb+
So glad you have solved your issue for now.

Thanks.
Yes, the service does seem to have settled down now since mid-December: hopefully it stays that way, as currently 4G is our only chance of better speeds here, at the moment. So as long as it generally stays 10Mbps or more downstream & 1Mbps or more upstream (which is the minimum I was aiming for), I'll be happy!
It's just the data caps now that prevent 4G from being a complete alternative to a good Fixed Line (or Fixed Wireless) connection.