im with you on this one jonboy -all the way !!!
get a tankbag
my oxford one - i got in a sale from busters didnt cost that much
its a tankbag
can be used as a tailpack
got a map pocket
a part comes off and acts as a bumbag
the back comes off with straps so can be turned into a rucsac.
lifetime guarantee
it even is the same colour as my bike
and the biggest plus of all
ITS NOT A TOP BOX