Legacy issues with National Australia Bank's UK banking arm continue to dog the group's earnings. NAB said that it had incurred an unspecified "increase in expenses largely related to further provisions raised for conduct and redress matters.""Conduct and redress" is not spelled out in the bank's June quarter trading update, but NAB clarified that it includes additional provisions for mis-selling payment protection insurance and interest rate derivative products - both industry-wide problems in the UK.NAB said that it recorded cash earnings of A$1.5 billion in the June 2013 quarter, or two per cent more than the average for the two prior quarters. Statutory net profit was $1.7 billion, up from an average of $1.3 billion in the two previous quarters.NAB said that revenue increased by one per cent, "reflecting good growth in mortgages and some improvement in customer margin."Expenses increased by two per cent, "including upfront implementation costs relating to previously announced changes to the Group's organisational structure and operating model", as well as from the higher UK provisions.The charge for bad and doubtful debts for the quarter was 10 per cent lower, at $489 million.In the UK, NAB said "banking cash earnings" were broadly stable. It said asset-quality metrics in its UK banking arm had improved slightly.The troubled UK commercial real estate book, which is now managed at the group level, declined to £3.9 billion, from £5.0 billion, at 31 March 2013.The ratio of loans 90 or more days past due and gross impaired assets to gross loans and acceptances was 1.78 per cent at 30 June 2013 compared with 1.74 per cent at 31 March 2013.