Hi,
I've been having the same issues and mine need to be replaced asap!
I recently noticed that Seat do "fixed price transparent maintenance" on their website but couldn't see any terms and conditions to state that
Cupra, specifically
Sub8 packs are exempt from this deal. Therefore front pads should cost £125 and font discs and pads should cost £299 (all in cost).
I therefore contacted my local dealer, got a quote for the parts plus fitting (£400 for pads, £1000 for pads and discs) and then challenged them on the issue of false advertisement and misleading customers etc. I ended up getting the dealer to contact Seat UK who initially tried to get out of honoring their advertised maintenance costs but today they relented. I am now booked in for discs and pads for £299 but they have informed me that they're updating their terms and conditions as a result of me finding the loop hole.
I would suggest contacting them and trying your luck.