Disco 1 Kick down cable seized ?

Hi,
The kickdown cable on my 300tdi autout EDC appear to have seized. The accelerator only has half its normal travel. On closer inspection the top cable on the follow diagram movers freely to pedal when disconnected at point 2 from the arm. However, the lower / kick down cable doesn't move at all:


If the kick down cable was broken I would expect slack movement but there is no play at all.
Has anyone experienced similar problem ?

seems like you need to replace it or at least drop auto sump and look

Yes, I'm going to remove the sump this weekend to see if there is anything obviously wrong. Given that the cable is blocked solid and gap C on the above diagram is currently 3mm the throttle valve itself is maybe stuck closed. All forward / reverse gears works ok. but I'm lacking any power because the accelerator only has half it's normal travel.
Has anyone any advice on what to expect when dropping the sump and possibly the valve body itself ?