rear springs on fourtrak


hi i was wondering were to buy new rear leaf springs for my fourtrak ive been to milners and they dont do a spring suitable for offroad. have found a shop on ebay sdn ltd they do a 5 leaf spring is this suitable for offroading i dont know any help would be appreciated the price for them is £145.95 + £25p+p for the pair including all shackles bushes and nuts and bolts is this a fair price ???? this is the ebay shop link
with thanks fatbob