Bluetooth issues with High Sierra

I've used a bluetooth keyboard and mouse with my Mac Mini for the past 8+ years, flawlessly and with no problems. Sadly, I've started having severe problems ever since upgrading to High Sierra.

The problem

It starts with a stuttering mouse pointer, and occasional missed key presses, the seconds later, both the keyboard and mouse will disconnect (at the same time). After waiting around 5 seconds, functionality returns, although this problem often occurs repeatedly for many minutes, before eventually going away. It occurs totally without warning.

Attempts to rectify

I've unplugged all external devices, ruled out any household appliances or other devices that may have caused interference (bear in mind the configuration has been the same for many years without issue), reset the bluetooth module and PRAM - I have even removed and re-installed the airport/bluetooth module physically. Annoyingly nothing has yielded any positive results. I have also replaced the batteries in my Magic Keyboard and Mouse, but oddly there seem to be less disconnects when using not-new batteries (I'm currently using ones at less than 30% intentionally), although this might be just a coincidence. Please note: both devices are disconnecting at the same time, so this is clearly not a single-device (battery related) issue.

I recently purchased a 2013 Mac Pro (the trash can), and was sad to find that I have the exact same issue with the new Mac Pro! I have since discovered many other people on the web complaining of the same problem, which pointed me towards it being a software issue. Upon inspection of the Console, I have discovered a large number of spurious log items relating to 'bluetoothd'. I have included a filtered dump of the log below :-

Further interesting discoveries, and points of note :-

• The bluetooth controller seems to be crashing and resetting (explaining both device disconnects)
• The issue affects keyboard AND mouse, never just one of them
• The issue occurs even after fresh restart - when simply browsing the web
• Both Mac Mini and Mac Pro are standard configuration, used primarily for X-Code and web-dev
• No unusual external devices are connected (just USB HDDs and phones)
• CPU usage is unaffected, not adding any significant load
• The problem happens in short bursts, often for a period of around 2-10 minutes, then going away for hours or more
• It happens at any time of day (even at 3am)
• My Magic Mouse was swapped out with a new one by Apple, this had no effect

Any insight would be appreciated. Apple seems to be ignoring this issue, but there are enough people out there with the same issue for it to be real. I sincerely hope there is a fix made soon. The only true resolution at this time is to stop using bluetooth, but that really isn't an option with my setup as there is no easy route for a cabled keyboard and mouse. That aside, its a totally unacceptable solution.