Hello Manclad from a fellow Manc. (Now residing in Rossendale). Our mh is over 3.5 tonne and class 4 and we use Bennett & Son, Fletcher Bank Garage Manchester Rd, Ramsbottom BL0 0DD for servicing and MOT. Really nice genuine people.
We had solar panels fitted by C & S Caravans at Accrington (who have also carried out bodywork for us in the past).
I know that neither are on your doorstep but we can personally recommend them.