neon indicator of shower switch indicator stays on?

I have just replaced a shower isolator switch but the neon indicator light is stayying on. The old switch had two connections for two earth wires the new one does not. There is a screw connection on the switch unit that holds the switch, should I conect an earth wire to that even though its plastic?

My loft wiring that connects to the switch has two earth (as mentioned) two red and two black wires. I first copied the connections as they were in the old switch but as the neon light stayed on I reversed the positions of the black and red wires (i.e. 1: red at front "reverse" 2: black at the front etc).

I am a little worried that as the indicator stays on it means that the supply is continuous and could overheat and catch fire even when pull cord states off?

Please help as I want to fix this a.s.a.p