Sounds like the Antminer S3 is perfect for your wattage limit, I have one but I am US based so I don't know how well it work.
Power compaitability is not an issue as the S3 wants 12VDC. Gerat thing about most small miners, they take 12VDC so I can basically slap them straight onto the storage batteries (small bateery controller in-between connects/disconnects the supply when the batteries get low).
If your S3 is collecting dust and you are willing to donate it, PM me and we could work out shipping.