Buenas dias ;-)
I replaced my Rover's rear exhaust silencer with one of these from eBay:
https://www.ebay.co.uk/itm/Endschall...EAAOSwfphaaF0x
This seller was listing them in UK Pounds in an English listing but doesn't seem to be doing so any more. Certainly, the seller was happy to ship to from Germany to the UK so maybe they'd be happy to ship to sunny Spain, too.
The part seems to be of good quality (it's still going strong, three years later) but I think it needed a little adjustment by the exhaust fitter to get it to fit. It's not too noisy, which I know is a criticism of others you can buy.
Good luck!