Re-Pitching on Slow Nottingham?

I brewed up a big (1.080) chocolate stout on sunday and pitched 2 packs of rehydrated Notty. I looked at the lot # and it was not in the recall. But 30 hours after pitching I have no signs of fermentation. Tonight I read that others have had slow starts but with mixed results. Any advice as to whether I should re-pitch or just wait and see. I am inclined to pitch 2 packs of S-O4 on top but I am not sure what will happen having to different yeasts battling for the delicious sugars of my stout. Thanks.

Pitch new yeast. I had some of the bad Notty and didn't get fermentation for almost 7 days. I even pitched a second pack not knowing there was a problem with the batch of yeast. Needless to say it tastes a little off compared to the 5 gal in the other fermenter that got a good pack of Notty and was rocking the next day.

Don't risk the beer, pitch new yeast.

I'm becoming increasingly reluctant to use any of my remaining packs of Notty. I'm also wondering what besides air might have made its way into a punctured sachet.

Sorry if I sound alarmist. This is by nature a critical issue.

Just to update my nottingham experience. Yesterday morning I was about to re-pitch 2 rehydrated packs of S-04 into the batch of stout. When I pulled the lid there was definite activity on the surface (I have fermcap at work so no krausen expected). My blowoff tube is 1/2 id so I was not suprised that there was no bubbling at that stage. At lunch yesterday it was bubbling nicely. So it took roughly 36hrs to get started but it seems like a normal rate of fermentation at this point. I will try to keep this updated for posterity.