It’s the rubber seal behind the flat plate (covered with the small torq screws) that leaks. Mine was leaking badly, so tried adding a little gasket sealant. Helped, but still leaked and then got progressively worse.
Removed all the gasket sealant and gave it all a good clean up, carefully resat the rubber seal with a touch of grease and retorqued all the screws properly and I haven’t had an issue since.
It will probably leak again but who knows when. VW won’t sell you this seal, you have to buy a new pump, but there are repair kits on American eBay that sell the seal included.