It appears we have very similar symptoms, here is my text from the other nottingham thread. Kind of a winded post....sorry
Well it seems I have this slow start yeast myself. The longest I have ever had a beer go before the airlock saw pressure was 48 hrs, and they have all at least bubbled some. Well this batch of nottingham (1080961099V exp. 12 2011) hadn't pressurized the airlock yet at 72 hrs, so I got a little worried. I peeled back the lid, and there was a shallow layer of froth on there and a nasty stench. I closed it up and went crap, "do I have some sort of infuction or what". I've used notty plenty, and don't ever remember that odor. Being the optomist that I am, I closed it up to let it ride. Now 5 days into this, it has finally lifted the airlock, but I haven't caught it bubbling. decided to check on the odor again, and it has now gone to "roast beefy".
Has anyone come up with any nasty flavors from this batch? I plan on letting this one go longer in the primary so if there are any off flavor's, hopefully it will clean itself up. BTW I have been fermenting this one at 70, to get the more fruity esters that notty can give on the upper end. That being said, I hope I don't end up over the top due to this being a "week" or "stressed" yeast.