Switched back to Avast Free (4 core shields + ransomware) but this time combined with VoodooShield Free v7.01 instead of MBAM.
Disabled or Removed:
Windows Defender + ConfigureDefender ('High' setting)
Wisevector StopX 3.05 (All shields, Firewall & HIPS 'High Security' Modes). WVSX retained as an on-demand, second opinion scanner
Reason for change: WD continues to be noticeably laggy on my system. Also this week Defender disabled itself entirely as it was unable to apply 'Microsoft Defender antimalware platform KB4052623 (Version 4.18.2202.4)' update. Having an AV switch itself off without any notification being displayed isn't great for starters but it was compounded by the fact the WIndows Security system tray icon hadn't loaded on boot either (which happens on occasion) so it was only by chance that I realised that Defender wasn't defending at all. WVSX which was running alongside Defender was active so I had some protection. I was able to subsequently apply upgrade on reboot but the fact that it switched itself off until it was able to upgrade is pretty poor. Decided to give VS another run.