it's a 16 or 18 mm hex from memory, spring one side and damper the other, that one?

It *is* a nasty one, everyone thinks they either cracked the block or stripped the thread, I don't know the factory settings, did both of mine by hand with a proper hex key and a ring spanner to lever until it felt right. I do know one person who broke the block.... so on that data point alone it appears that the block will fail before the threads...

My advice is watch it, open the bonnet every day or two for 3 months, if it hasn't moved by then you'll be OK.