Did you move and resite the dish yourself?
have you damaged it in any way ... dish shape or lnb feed support arm/s
is the lnb in exactly the same place 'focus' wise as well as skew ... ( at the same distance from the dish face.)
are all the cables OK.. no kinks/ good joins ...and do they now run near mains or other cables
is there anything in the way towards 28.2/5e ... sometimes it can catch even seasoned installers out .. such as a tv aerial, tree branches, wall or rooftop, chimney cutting part or the bottom of the dish off, telephone or mains cables suspended from poles etc...
is there anything local that can cause minor interference but enough to knock weak 28.2/5e out..
is the receiver placed in an area that it gets very hot
was the previous site shading the lnb from the sun
just a few things to go at....
best of luck..