The switch priced at £6.39 with a printable PDF wiring diagram can be found here.
http://www.marcleleisure.co.uk/store/switch-step-position-grey-p-3184.html
The wiring diagram shows a rear view of the 5 terminal switch, not 6 terminal as suggested and the common terminals look to be numbers 1 and 4 which are on the outside edges and not in the centre as would normally be on a six terminal switch.
If you need to purchase a switch, do check the colour matches the original surround frame. I think they are available in black, dark grey and light grey. Some suppliers refer to the colours as charcoal, graphite and light grey (silver)
