I've had some issues with the clutch in my Defender today. First noticed that the clutch pedal wasn't returning to the top position fully, appearing to get stuck half way up. Later on today, this developed into a clutch pedal that feels hard towards the bottom of its travel and won't allow any gears to be selected without some force and crunching. With the landy in gear and the clutch fully depressed, it feels like the clutch isn't fully disengaging as it tries to nudge forward. Any ideas would be greatly appreciated.

Most likely your pushrod gone through the clutch arm. Could be a hydraulic issue, have you checked for leaks and fluid level in reservoir?

Also the colour of the clutch fluid can be a pointer to something serious