Have an 03 freelander td4 with a clutch problem, the pedal seemed to delay returning to its normal position when engaged, and then suddenly the pedal went very loose and ultimately was unable to select a gear. Reservoir at master cylinder was dry so topped up with fluid but problem still there

Most likely still has air in hydraulic clutch slave system. Many transmisions will have dificulty shifting if clutch doesn't full disengage. If air is in system it won't allow full disengage thus difficulty in shifting even possible grinding gears

Air is replacing the fluid, so seeming as if there is no fluid loss. It is escaping someplace not obvious, such as inside the bell housing along the actuator rod.

If you needed a new clutch in the first place, it would be a good investment to put in an overhaul kit on both master and slave cylinder, or, if you find corrosion, replace both.

You have a leaking master or slave hydraulic clutch cylinder. I recommend you replace both

Definitely a hydraulic issue. Iknow you said they were both changed, but its usually the master & slave assembly that go faulty on the Freelander. Both parts come filled with fluid and pre-bled and only require fitting, no bleeding. Check with garage to make sure they did not split / bleed them.

Sounds like a clutch control problem. Did you check the fluid in the clutch master? If you get a leak and run out of fluid this will also do this. This vehicle uses DOT 4 brake fluid in the master.

There is a spring on the clutch fork which resists pushing the pedal and returns the pedal to its proper rest position. It would be on the bell housing where the slave cylinder is attached. Possibly that spring has broken, and hopefully you can replace it without pulling the bell housing off the engine block..

if its a clutch cable it been adjusted to tightly, common after a new cluth, will start to lift after use but double check the cable is not to tight as it may snap. if its hydrolic then the oil coild be low or air locked.

Have the machanic check the catalyst converter.

If you put your car in 1'st gear, release the clutch pedal and nothing happens, absolutely the clutch is faulty.
Cheers

i have just replaced an 03 civic ex clutch and transmission bearings due to a customer being too harsh on it. It sounds like its got a little life left in it if you are easy on it. 

if there is adjustment in this model use the below walkthrough to adjust it.

adjust the clutch pedal, 

1. if you look up on the top of the clutch pedal, the first thing you should see if a clutch pedal position switch, and right behind it there is a locknut, looens the locknut. once you loosen it, back off on the pedal position switch or adjusting bolt untill it no longer touches the clutch pedal. 

2. now behind the clutch pedal, there is a pushrod. and on that pushrod, there is a locknut, loosen that locknut. Now turn the pushrod in or out to get the desired height and stroke at the clutch pedal. 

The freeplay is the amount of push on the clutch pedal to where is starts to have resistance from the top. I have usually been told it should be set at 1 1/2-2 inches of freeplay.

Once you set it, tighten the locknut on the pushrod. With the clutch pedal released, turn in the clutch pedal position switch untill it contacts the clutch pedal. then turn it an additional 3/4 to 1 turn. And tighten the locknut.

Now on top of the clutch pedal switch, there is a clutch interlock switch. Loosen the locknut on that switch. then press the clutch pedal to the floor.

release the clutch pedal 15-20 mm (0.59-0.79 in) from the fully pressed position, and hold it there. adjust the position of the clutch interlock switch so the engine will start with the clutch pedal in this position. then tighten the locknut on that switch.

Hope this helps