Have a look at this guys:
http://www.iam.org.uk/Pressroom/News_Relea...ive/nr0115.html
The Institute of Advanced Motorists recommends using all available lanes until the restriction.
To quote "In our view, the sensible advice for all lane merging situations is that drivers should reduce their speed and increase the gap between themselves and the vehicle in front. All available lanes should be used right up to where the lane closure begins and vehicles should merge in turn - one from the left, one from the right, and so on."