That's probably because whoever wrote the article linked above didn't bother reading the written answer properly.
House of Commons Hansard Written Answers for 06 Jan 2010 (pt 0027)
The adoption of the Future Rotary Wing Strategy, announced by the Secretary of State for Defence on 15 December 2009, Official Report, column 99WS, has resulted in a number of changes to our planning assumptions, although the only change to OSDs is for all marks of Sea King which will now retire in 2016 rather than 2018. We are procuring 22 additional Chinook by 2020, increasing the fleet size to 70 and subject to the Defence Review and individual investment approval the Merlin Mk3/3a fleet is due to switch from the Royal Air Force to the Royal Navy. Further Merlin Mk1 may potentially be modified to deliver Airborne Search and Control capabilities.