Update: I opened up the machine, couldn’t find any obvious fault with the switch or the control card. Re-assembled and the machine is now sort of working.
Sometimes it will not turn on, but if it is turned off and on at the wall it then turns on and works normally! The issue of it turning on by itself in delay timer mode has gone. I suspect it may be a power supply fault to the control card maybe but at the moment I am leaving alone.