First post! Had a quick search before posting and couldn't find another however apologies if I've missed it.
2 for 1 minicruises are back with P&O. £72 on foot to Amsterdam, Bruges, Zeebrugge and Rotterdam and £74 motorist minicruise to Rotterdam £74. 2 nights plus an extra night can be booked for £10pp and you must find own accomodation.