Sorry but after trolling through what seems about a hundred pages of posts - I couldn't find an answer to my question.....
I'm not a complete mechanical or electrical numpty but Mach is written in some wierd off world language that confuses me totally

Q. As the Gecko 540 has only 5 inputs, can 2 switches be used for each axis and wired in series and connected to ONE pin only ie. ++x,
--x and home x all set to, say, pin 2?

Will Mach recognise that it is travelling in a minus direction and trigger --x & home and when its travelling in a plus direction, trigger the ++x?
If it needs 2 pins per axis - i'm gonna run out, bearing in mind one is the e-stop!

Or is it best just to use --x / home and set soft limits for opposite limits of table movement and only take 3 of the 5 available pins?

Any diagrams or pictures of set-ups on a X2 mill would be appreciated

You can conect as many switches as you want in series and use 1 input. Mach will light up all of the ,imit switch lights when one is triggered but Mach doesnt care and unless you can not see the machine it will not matter to you either. The important thing is a switch being hit triggers the E-Stop and you can then physically look at the machine to determine which has been hit.
 You can also set up your Home switches in the same series loop as the limit switches, in fact you can use one of you limit switches as a home. When doing a homing move Mach will treat the limit as a home switch and thus your limits will not trip, when the homing is complete Mach automatically treats the switches as Limit switches again.
Hood