How to replace the power on/off switch.
At present will work if I hold down the power switch. It will not stay on by it self.

Jo, October 2016

First before anything else buy a replacement switch
Then dismantle the machine and remove the old switch
Then fit the new switch and reassemble it all.

You may need a special tool such as a Torx driver

There are on-line spare part suppliers for domestic appliances.
In the UK e-Spares for instance.

Good Luck..., October 2016