Preventing decimals with NSNumberFormatter

I have an NSNumberFormatter which I'm trying to use to generate a whole number of GBP (£) from an NSNumber. I keep getting two decimal places regardless of which incantation I try. My code is:

NSNumberFormatter *fmtCurrency = [[[NSNumberFormatter alloc] init] autorelease];
[fmtCurrency setNumberStyle: NSNumberFormatterCurrencyStyle];
[fmtCurrency setGeneratesDecimalNumbers:FALSE];
[fmtCurrency setCurrencyCode:@"GBP"];
[fmtCurrency setCurrencySymbol:@"£"];
txtTotal.text = [fmtCurrency stringFromNumber: result.Bill ]; // this is an NSNumber