Internet Security System - Combined (or separate with each from a different company) Antivirus and Firewall systems.
They have been known in the past to mess up speed tests. Those problems seem to have been largely (not necessarily completely) sorted out at ADSLx and FTTC speeds, but I'm wondering if yours may not be brilliant at full speed FTTP 300Mbps downloads.
Also, if you are speed testing at this level through that wireless system any results are suspect. Particularly if anything else is running on the system or any computers/phones/tablets.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. 200GB. Sync 76102/14089Kbps @ 600m. BQMs - IPv4