I've just come across a difference in spools on these reels, from what I can gather it is based on whether you bought your reel in Australia or the USA. I've attached the PDF of the schematics, the 2500FD was sold in Australia with one drag washer while sold in the USA with three drags washers. These two schematics are taken from the Shimano Aus and USA websites respectively.
I found this after purchasing a second hand 2500FD with only one washer. It doesn't have the recesses milled in for eared washers either so I am unable to expand it myself. It's got some corrosion on the spool so I may have to look at tracking down a new spool with the three washers. I was guessing it'd be the same for the Stradic 2500FH although BigT did a tute on his Australian bought reel and it has three washers (http://alantani.com/index.php?topic=914.0) yet the Shimano Aus schematic for it only has one, go figure?
Just a heads up for anyone one else who runs into the same problem, now to go spool hunting so I can put together a nice rig for my boy!