After some further thought I've come up with the following solutions to fitting the Mondeo Flywheel to the AJ30 engine:
Ring gear wrong: Fit a Mondeo starter (not a direct fit) or replace the ring gear
Thickness: Machine up a spacer
Spigot bearing: Machine up a housing for the spigot bearing
Dowel alignment: Make adapter/leave it (non critical)
Looking at the amount of work involved I think I'll have to write it off for now, I may come back at it when I've got further with the car.
Or I just save up for one of these:
http://ttvracing.com/engine-types/?m...ls#prettyPhoto[iframes]/0/
For now though the dual mass flywheel will be going back on!