The spring in the assembly is just to pre-tension the pedal and plays no part in the clutch operation.
There are two types of clutch cable fitted to Xantias. The self adjusting and the manually adjusted, depending on your vehicle. They are not inter-changeable. This may be why your clutch pedal is too high, as both cables need to be set to minimum clearance.
If you are regularly snapping the cable clip, you need a new clutch!
The only reason I have a box of these old clips is because I have fitted quite a few new ones on cars where they have expired. You only need one as a spare.
Looks like your £50 was a bit of a false economy. You need to ask your mechanic if he bought the cowboys hat or did he just find it?
Handyman