Cannot connect to LAN - Upstream2 Plate Amp

My Upstream2 Plate Amp is very difficult to connect to LAN. When I power up the unit and the LED starts to flash the unit automatically connects to WiFi, because I already used it with WiFi and it has the settings already loaded. When I connect the LAN cable the unit will not switch to LAN but keeps the WiFi connection.

I tried removing the mains lead and powering up again, with the LAN cable connected. But the LED flashes and insists that I complete the WiFi setup through the APP.

The manual is not helpful, it just says ‘insert the LAN lead and it will connect in 10 seconds’ which is not the case for my unit.

Any suggestions please? Do I need to permanently remove the WiFi settings from the unit before I can use LAN?