Connection speed unchanged but lag for days

[#1]

Hi,
could you please check my connection as I'm getting the same speed test results as always but everything has been laggy and timing out for the last few days, be it via ethernet or wifi, and regardless of what equipment or OS in use 
Thank you

[#2]

Bump 

[#3]

Nothing obvious showing, the line has been connected for over 10 days without dropping. The sync speeds are where I'd expect.

[#4]

It's still laggy and I'm the only person online in the house.
My wifi is too slow on my smartphone so I'm having to use my mobile data allowance even when right next to my router.
I'm on a wired connection on my desktop and this page took a couple of attempts to load due to timeouts.
Any ideas apart from reboot the router? That was done as you have said about 10 days ago. The lag has been present even before that power outage (meters upgraded by energy supplier).
Thanks in advance!