There are other compnies that sell the complete kit of wheel + jack & brace (in a bag) for less than Seat.
Yes, the Road Hero space saver is one alternative option.
When I was considering buying my non-VAG car, the dealer offered Road Hero spare wheel kits as an option. However, for my car at the time I seem to remember it was a full size spare rather than a space saver and the full size spare took up valuable boot space. Like
@Yern, I got the dealer to include an OEM factory space saver - which fits under the boot floor in the spare wheel well - as part of the deal

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Looking for a Road Hero Spare Wheel Kit
Cupra Leon (RH034)? At Carnoisseur.com we can supply you with a Road Hero Spare Wheel Kit
Cupra Leon (RH034) - available to buy online and delivered to your door.
www.carnoisseur.com
For the Leon, one of the pictures at the link above shows the Road Hero spare wheel in a bag, and the accompanying kit (jack, wheel brace etc.) in a separate bag. From the pictures, the bagged space saver in the boot isn’t in the spare wheel well, but sitting on top of the boot floor, taking up boot space. Whether that means a Road Hero space saver won’t physically fit in a
Cupra Leon’s spare wheel well isn’t clear (maybe the pictures are generic and not
Cupra Leon-specific?) but for anyone who considers buying this brand of space saver spare, it’s something to check out, especially if usable boot space is important to you.