fuggles. In an oatmeal stout the hops should be there more for balance than anything else (shouldn't be overly noticeable in terms of flavor and aroma) so the variety shouldn't matter all that much, but I agree that an english stout should have english hops.
Primary: English Gold
Secondary: 2013 Dark Stock (on oak), Wee Heavy on oak
Bottled: Sir Suspicious Oatmeal Stout, Victorious Brown Ale, Wee Rambunctious Scotch/Belgian Hybrid