Alien invader in the garden

This is probably my least pleasant blip of an invertebrate. Taken in my garden, it is a New Zealand flatworm (scientific name: Arthurdendyus triangulata). It has been found in Britain since the 1950s, when it was first seen in the Royal Botanic Gardens in Edinburgh. The problem is that it is a nocturnal predator of earthworms which play an important role in maintaining soil fertility in both agriculture and gardens. They apparently feed on worms that live in surface layers of the soil. We have lots in our garden, unfortunately, and Central Scotland is a bit of a hotspot for them. They shelter under wood, flat stones, polythene sheeting and bags, etc. This one has slightly uncurled from the disc-like curled up shape they adopt when sheltering during the day. This one, still quite scrunched up, might when stretched out fully, be more than five times longer than this. It's not very scientific of me, but ugh!!!!