Further TC650 on/off question?

Thanks to Anchorman for the reply to attached thread >> Hoover TC650 On/Off Switch problem?
The On/Off switch will no longer stay pressed in (On) so need to replace the switch but how easy is it to do? I looked under the worktop at the rear of the switch assembly and you can't appear to get a screwdriver at it, as the drum is very close, any suggestions?
[ANCHORMAN on/off buttons on these models dont stay in. the power to machine is held by the relay very common fault. easy test hold the on/off button in and keep pressed in if machine starts turning and stops as soon as you release then its the relay pcb] ## how do you get to the relay to change it?