LONDON, July 7 (Reuters) - British home shopping firm N Brown Group Plc (BWNG.L) on Tuesday 7 July posted a slight slowdown in its rate of sales growth and said its gross profit margins had continued to fall due to an increase in bad debts.

Simply Be

The Manchester, northern England-based group, whose catalogues include Simply Be, Oxendales and JD Williams, said turnover increased 5.1 percent in the 18 weeks to July 4.

The group said the outcome was in line with internal expectations. It compares with sales growth of 6.1 percent in the eight weeks to April 25. [ID:nLR519086]

Gross profit margins were down 1.5 percent, having been down 1.2 percent in the eight week period, driven by an increase in bad debts.

However, N Brown said the rate of growth in money owed by customers had slowed to 8 percent, compared with 13 percent at the year end.

It said the margin decline had been offset by operational cost savings and reduced interest charges, adding that the group's financial position "remains strong".

Shares in N Brown, which have increased in value by 17 percent over the last year, closed Monday 6 July at 211.5 pence, valuing the business at 581 million pounds ($945.2 million).

(Reporting by James Davey, editing by Miles Neligan)