[Liparis]

These slugs eat decomposing material as well, but have a preference for spuds when they find them. Some varieties are said to be less prone to keeled slug attack, but I wouldn't want to chance it. You would be better to do some sort of control or this might be an ongoing problem for you, probably nematodes may be the ideal way to go.
Bill.

[James Kilkelly]

It may have been a two pronged attack!
I wonder did you come across any wireworm in your potato beds Organicgrowingpains?
Although most active in August, the wireworms create small tunnels in the potatoes which entice the slugs in to create the larger holes.
How to manage the top two potato pests, Wireworm and Slugs.

[Organicgrowingpains]

Yikes! I did not know what they looked like until I followed your link. Two things immediately struck me on reading it.
We covered this area in compost and kitchen waste such as cabbage leaves and rotting fruit then covered it all in cardboard and black plastic.It was a no dig area so the ground was not turned.
In the photo there is a plot directly behind mine but up to a few weeks ago this was all grassland .
I dug up some the Colleens this morning and they have no sign of worm damage?

[Liparis]

Ys, the wireworms and slugs often work in tandem.
Bill.