Was checking the mode switch on the front amplifier panel and switched it Left to Off. When I tried to switch it back Right to ON the slide switch was loose and it wouldn't switch back on! Feels like the switch is broken, do I need to dismantle the speaker to fix this?

The switch handle has a couple of small fins that break at the backside.
You will be able to swap the broken handle with one of the remaining two and regain full functionality
as they do not all grip their respective switches the same way.
Yes, you will have to take the amplifier off the tower to fully release the frontpanel and access its innards.

Martin

Thanks Martin. There are a couple of stays connecting the panel to the amplifier, these can be released by inserting a screwdriver from the side and the panel drops forward. 3 screws release the PCB and the switches drop out. The small fins that hold the 3 switches in place were all damaged to varying degrees. After putting the switches in the correct position I slid them back and reconnected the PCB. All is working fine now. Thanks again for your reply.