In case anyone was interested, had to change all 4 discs and the pads again today. Genuine parts were fitted last time, now up to 33,000 miles in 4 years.
None of the pads were sticking, all the sliders and calipers are working as per design.
Car does spend 2-3 days in a row out of every 8 stationary, but does do 4 x 50 mile commutes in between.
The Panda has £13 discs on and gets a lot less use, its brakes are still absolutely fine.
These Jaguar ones really are made from recycled Lancia Betas and cheese.