I think the reason they were put there was for Asda traffic to turn right, instead of having to add 20 seconds extra to their journey going round the roundabout. Now instead you have to wait for the filter light to turn green, and then sit in more traffic lights! I don't mind the lights at the roundabout, but coming down the main road, it's stop-start-stop-start-stop-start as they're not in sync.
The reason the lights were put there and Asda re-routed from car park is for the forthcoming pay to use motorway tolls. The roundabout didnt have power to it, now it has. Same as Bidston Moss now has after the lights there. All other roundabout main junctions up the M53 have power to them, now so do 2 and 3.
It will take a day to drop a toll barrier in place, plug it in, hey presto, job done.
Thats also the reason to turn the Asda traffic away from the junction.
I have a friend involved in the planning and preparation for the tolls and the logistics of it, it wont be long. Couple of years at most.