I used to deal with a few Law firms in the Manchester area back in 2006-2011 I can really recommend one called Slater Heelis They offer a wide range of services and used to operate from a number of locations around the Lancashire area.
Another firm which is well known is Eversheds I used them personally when I had an employment dispute back in 1998! They had since merged and become Eversheds Sutherland, but I am sure they are still just as great an outfit as they were back then.