Hi Chris,
I had the same problem with the hydraulic clutch on the Rover gearbox. I ended up making this
I attached a short rod to the pedal which goes through the bulkhead. It is connected to this contraption. As the pedal is depressed it pulls the rod which creates a pushing movement on the other side of the pivot through a rocker arm arrangement.
It took a while to figure out but it works really well.
I measured the amount of movement at the pedal and also the amount of travel that the master cylinder required to be fully depressed. (I think we all know that feeling).
I then mocked up the rocker in cardboard to get the measurements I needed.
The whole thing needs to be well attached to the bulkhead because of the forces involved.
As you can see I am not running the original servo (mine is in the boot) so I am not sure how you will get around that but the above method has worked for me.
If you need any parts machining up let me know
Hope this makes sense as it is difficult to explain.