Actually, I didn't fully answer as I was waiting for the fool to come back after I already demolished the first half of his argument.

We publish on Twitter a file that contains the number of the block that the hash will provide the client seed. That file also includes the server seed and ticket list. That's everything you need to verify the result.

Edit: I forgot to mention that the server seed is also on display on the Provably Fair tab of the lotto page all week.