Garden snail Helix aspera, VC. very common and i think Europe's largest land snail They are edible and was introduced to Australia for that purpose and as usual escaped and is big a pest there as here.
The species has been renames, it is now Cornu aspersum (in dutch segrijnslak), apart from Helix pomatia it is Europes largest land snail.
I've eaten these. I wasn't impressed. (But probably the snails were less impressed). I didn't know they were introduced to Australia for eating.