Dec 7 (Reuters) - Britain's FTSE 100 index is seen to open 11 points higher at 7,358.6 on Thursday, according to financial bookmakers. * ROLLS-ROYCE: Air New Zealand Ltd on Thursday said it would cancel and delay some international flights over the coming weeks because engines on its Boeing Co BA.N 787-9 jets manufactured by Rolls-Royce Holdings PLC required early maintenance. * ROYAL MAIL: Britain's Royal Mail said on Wednesday its mediated talks with the Communications Worker