Fibre Speed periodically drops - needs router reboot

[#1]

We've had basic FTTC for about a year.  Every week or so, the download speed drops from a normal 35 Mbps to around 3 Mbps, and the router needs rebooting, whereupon the full speed is immediately restored.  Any ideas why/what to do?

TIA

[#2]

Hey @Cliff_g,

I'm sorry to hear that you've been experiencing this issue with the speed. I've tested the line today and haven't been able to locate any underlying faults, so it's hard to say what might be causing this to occur. When it does occur, are you connecting to the router via Wi-Fi or Ethernet cable?

[#3]

Good point.  All our devices are connected via Wi-fi, however, next time it happens I will plug in via ethernet to see the speed, hopefully eliminate the wifi as a problem, first.  And get back to you here

[#4]

Thanks for confirming this @Cliff_g, just let us know how you get on and we'll be happy to help wherever possible.