Which seal do you need? All the main ones are shared with a normal M47, so are still available (or were last time I looked). The diff is what usually leaks though - are you sure it's not that?
I was suggesting you could swap to a complete LH2.4 setup (flywheel, wiring loom, ECUs, etc), but now you've found a flywheel, that sounds a lot easier. Shipping ain't gonna be cheap though
cheers
James