Did you pitch enough yeast? My green-apple beers were traced to using expired dry yeast, not making starters for liquid strains, and just plain not pitching optimal yeast counts into my wort.
And I don't make many beers over 1.050 so its not much work to make a starter for liquid, or hydrate my dry yeasts (or pitch extra if they're expired).
I've kind of given up on nottingham completely.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10