I purchased 3 deco M4r in April 2020 and use them in router mode with a virgin media SH3 in modem mode, when they were first set up all working ok with speeds up to 200Mbps as provided by VM, this is via a lan cable and wireless.

Over the last month its gone to 80Mbps and the only difference is the firmware.

The SH3 is in modem mode and when put back to normal mode i get high speeds via the SH3 WI-FI.

Tried all sorts but still can not get the full speeds via the M4's

Any ideas? (even had a new SH3)