Pop over to Craft Telly as I'm sure someone else had this problem. I'm just about to go out otherwise I'd have a look through the threads for you. If no one's answered you by the time I get back I'll have a proper look for you.
Many thanks for all the replies, I am still waiting on reply from Spellbinders web site, but I only e-mailed them on Friday. However, here is what I ended up doing. I got a narrow screwdriver, and pushed the centre out of the handle completely. I then got a length of washing line (ordinary string would do as well), and tying a knot securely at one end, pushed it through the handle then completely through the 'bulb shaped' part, and tied another knot so it fitted inside it. It worked a treat. I've also been to Homebase, and bought a long bolt and nut. Again, you fit it through the handle as before, then making sure the nut is inside the bulb, tighten the bolt through the nut. It worked as well. I hope this helps other people. As I write, there is a handle for sale on Ebay - at present, bidding is just below the £19 mark.