Finally got around to getting my old 200TDI back together and just about to fit the flywheel housing (new Dowty seal fitted). What is the general opinion on this- gasket or sealant or gasket with sealant? I have the ERR1440G original style gasket, which has the raised ribs to help seal, but wondered if others have used sealant too, or just not bothered with the gasket and used sealant only?

After all the work, I really don't want it to leak!

I just used the gasket on mine, 3 years later it’s fine - no leaks. I can’t remember if I used sealant aswell but I doubt it, i just hold gaskets in place with gasket positioner glue when assembling

Used gasket on mine and I would hazard a guess blue hylomar as well, but it was aboyt 5 yrs ago so cant be 100 percent on the sealant.
Make sure you use a genuine/quality rear main seal and the supplied installer tool, a little loctite on the metal outer bit of the seal helps keep it in place and the seal lip and the crank must be dry on assembly.

Thanks chaps. Used Turner seal in the end. Fingers crossed!