I'd read the Lidl container very carefully. Their own advertising leaflet claimed it had antifreeze in. Having read that I gave the actual product a wide berth.
Mercedez-Benz sell antifreeze screenwash additive which is simply added to the existing water/screenwash in the tank to add antifreeze protection. This would allow you to use whatever screenwash/water you wanted and still have it not freeze by adding some of this (paint-safe). Search eBay for 'Mercedes-Benz Anti-Frost Additive' (under 5 posts so can't post URLs ).