mike,
now i know menzies i used to load them at stn, they are a good company to drive for and pay decent money and use good kit too, fhs, merc actros with good trailors.
imho go with menzies.
they have a couple of big sheds up at htw and there motors always jump the q.
menzies are also a big handling agent at heathrow so you will get to go airside to load direct on to aircraft too.
they do alot of motorway runs and also up to prestwick where they have another depot as well so you will run up an down on that run.
shift work of 4 on 4 off days and nights from memory, uniform supplyed and usually you keep to the same motor, tons of o/t as well.
hope this helps
chris