£1500 for a used PTO centraliser ! I think you can buy a good new copy part from some dealers for around £800, do you need one or want one I've found that most kit fits with a longer shaft, you can also move the shaft under the Rockinger with a home made bracket but the shaft will hit the axle when the Mog is fully loaded so by the time you've made a bracket and made a thinner shaft (not easy) a banana box would be the best option.
Moose