They live in damp places, so try to keep the area dry if you can, I used ant powder on the area when we got them in the utility area a while ago, and haven't seen any since! worth a try!!
We have them scuttling around in the bathroom at night. I tend to leave them alone and only ever see 2 or 3 at any one time.
Apparently, they don't like cloves or Boric Acid. If you go somewhere like Homebase or B&Q, they will have a suitable insecticide to deal with your slithery house guests.