Limit Switches, EStop and Spindle

Thanks again for taking the time to reply.
Attached is a labeled photo of my wiring to the BOB

Interestingly, I have noticed that when I detach the parallel cable, the relay powers on! This seems wrong!

What type of limit switches, NPN or PNP?

As I understood, your E-stop is connected to ( P10 <-> GND)? It's right connection, I don't understand why it doesn't work.
And what about spindle, what do you have in (Machine > Hal meter > Pin > pwmgen.0.value? )
Possibly, you have inverted signal of PWM on your board , when you set 0 on board you get 10V and when you set <maximum value> you get 0. Try to change values, what you get?
To run without E-stop, change line
net estop-ext <= parport.0.pin-10-in-not
to
net estop-ext <= parport.0.pin-10-in

The limit switches are PNP:
www.automation24.co.uk/inductive-sensor-...wqRnEMhoC9lQQAvD_BwE

Maybe I need some extra components in the circuit?
Maybe these could be messing up the other components(spindle and EStop)

I also just found this on
en.industryarena.com/forum/breakout-boar...-wiring--373194.html

It looks like I may have mine wired as an NPN
and might try this to see if I get a result!

I just tried the circuit but all it does is limit the voltage change to something tiny.
with the existing setup I get a voltage drop from around 9 volts to close to 0.
I have tried inverting the pin but still no response from the GUI.

I tried your suggestion with the EStop line of code but then I cannot toggle the GUI power switch rendering everything inactive!

With the spindle Hal meter, the pwmgen.0.value changes as expected from 0 upwards/downwards as the +/- button is pressed in the GUI
I have inverted/uninverted the spindle signal using the Stepconfig Wizard several times but I always get +10volts form the BOB pin