I found a way around it...
Boot into recovery mode by holding the volume up and power buttons and reset the phone to factory settings after this you get around 15 seconds of full access before "demo mode" starts. During these 15 seconds you need to have your phone plugged into a pc, enter developer settings (tap build info in "About Phone" 5 times) turn on usb debugging and allow access to pc then remove these 2 apps using these ADB commands:
adb shell pm uninstall -k --user 0 com.tct.retaildemo
adb shell pm uninstall -k --user 0 com.tcl.demopage
If you take too long "Starting Demo Mode" will appear and you'll be locked out of the device and will need to repeat the process..
After this your phone will be out of demo mode until you next factory reset which will then annoyingly reapply the demo mode.