No there are no laundrettes, only on the spirit and celebratio.
No there is no laundry for self service, but there is a laundry service via your cabin steward. It is expensive though, wereon board last week, think it may have been £2 for a t shirt. You can wash small bits in the cabin, and hang them on the small line in bathroom, they will soon dry. Towels are supplied, so dont waste the room in your case by taking your own..