Job done!
Got replacement plastic sleeve and clip this lunchtime. Only cost £5.26 for both bits! (Wilmoths, Folkestone, official Citroen dealers).
Attached plastic sleeve to pedal and put the metal clip HALFWAY ON. Got under bonnet, released clutch cable (self adjusting type) and pushed cable in as far as it would go. Then got into footwell and positioned the pedal so I could feed the plastic sleeve over the end of the cable. I then used a small wooden pestle from my kitchen (it was all i could find that would fit) and forced the clip into position. Presto!.
Then the tricky part. Having got the pedal into position and feeding the bolt through, it was frustratingly difficult to hold the nut at the right angle to get it to take. I used a tiny bit of blutack to hold the nut in an open-ended spanner, but trying to hold the spanner in place, keep the ratchet on the other end and keep the torch shining in the right place proved to be a right faff! Eventually it took, tightened it right up, and reconnected the spring. This is far, far easier than the spring on the S1 version!
Reconnected the clutch cable under the bonnet (again, easier than the manual adjust type), and refitted ancillary bits and pieces. Tested to make sure all OK.
Interestingly, my GF says the clutch is now a lot smoother and "freer" than before, so I'm wondering if the auto-adjust mechanism on the cable had maybe become snagged somehow, and by releasing it and resetting it has sorted itself out?
Anyway, I'm so glad it's all over, I have a happy GF, a not too beaten up body, and haven't had to fork out for repairs which we frankly can't afford at the mo!
One final thought:-
I didn't take the seat out this time, and therefore was not lying completely upside down on my back, but more of at an angle with my legs out the door. This, with a big thick cushion and loads of covering on the door sill, made for a much less uncomfortable position. I would advise a good powerful torch though, and one that has an adjustable beam.
Many thanks to all of you who offered advice and encouragement (and brandy!), and to all previous posters on other threads who have offered their knowledge on this subject.
Peter