I've fixed a couple by cutting the barb off with a dremel, then drilling and tapping the hole to 1/8 BSP (you guys can use 1/8 NPT instead).
Caution- put grease on the drill & tap to catch the swarf, then drill and tap as shallow as possible- there is a valve in the bag behind the entry. I clamped the bag down on the mill to do this machining.
Then I screwed a 1/8 x 3/8 nipple in and got Pirtek to crimp a 3/8 flare fitting to a new hose. For the top end, cut out and re-use the original 5/8-18 UNF flare nut fitting.
I used 3/8" MPH 08 hydraulic return line hose from Pirtek.

Ignore the yellow tagged fitting shown on the other end of the hose here- it's 3/8 BSP. I just put it on for pressure testing.

[edit] There are other possible ways to fix the hose, see Todd Miller's excellent site- //www.austinamericausa.com/ 

Scroll down to technical > suspension.

Kevin Dr Mini in Australia (i think) has fixed a few with good sucess, mainly where the hose fits into the bag if i remember correctly.

Brian,

change of plans. Thanks for the offer.

I think I have one that's pretty much junk. Maybe you can save it. Throw in enough for a six-pack and it's yours.

Anyone have a clapped out hydro bag they would donate to me?  I'm wanting to try to fix mine, but would like to practice

on something else before I screw up mine.

I'll pay the postage.

Mike