Waterside Centre on Thames Valley Park that hosts groups from Berkshire Scouts
You'll need enough leaders to have one per five scouts, plus two to remain on land, and one home contact. It's recommended to do this as a spring or summer activity.
Contact WWC through their website at http://www.wokinghamwatersidecentre.com/ and book a session. They have group discounts for scouting groups in the Berkshire area.