Maintenance/cleaning of the alcantara can be found [url="http://www.alcantara.com/en/experience/manutenzione/pdf/manuale_eng.pdf"]here[/url] (you'll have to scroll down the pdf to the english (that's if your Italian isn't fluent

)
Previously I've just used a small amount of gentle detergent (woolite clothes washing liquid)in a bucket of warm water & just wipe with a damp cloth/sponge and dry off, & on the leather bits you can use the same or a specific leather cleaner but be carefull not to get it on the 'suede'
Hopefully one of the guys will be along shortly to run you through removing the seats