Lidl has moved fast to ­appoint Ronny Gottschlich as its new UK MD after the shock departure of Frank-Michael Mros.

Gottschlich becomes the German discounter's third UK MD in two years. Mros, the former head of Lidl Germany, was in the role for less than a year after replacing Marcel Oosterwijk, who left in 2009.

"We are pleased to confirm that Ronny has been appointed the new MD of Lidl UK with immediate effect," the discounter said in a statement. "Ronny has been with Lidl for 10 years now and has worked for the past seven years in the UK as a director."

Lidl refused to expand further but it is believed Gottschlich was a regional MD in the south of England before his promotion.

He joins at a challenging time for Lidl. The high turnover of MDs was symptomatic of the difficulties it was having maintaining strong sales following a period of double-digit growth at the start of the recession, said one supplier.

"The biggest problem is the promotional culture it has been forced to embrace," he said. "It has been forced to do more and more promotions, which it funds itself, and sales are flat at other times. It needs to decide if it wants to do EDLP or be a mini-supermarket that does as many deals as the big four."

Despite slowing, Lidl's sales have still outperformed the overall grocery market, thanks largely to a strong store opening programme. The most recent Kantar figures for Lidl show sales were up 5.0% in the 12 weeks to 5 September, whereas the overall grocery market grew 4.6%.

Lidl isn't the only discounter to have experienced a lot of changes at the top. Aldi's UK and Ireland MD Paul Foley stepped down in August 2009 and was replaced by Armin Burger, who lasted just three months. The UK business was controlled from Germany until Aldi appointed joint-CEOs Matthew Barnes and Roman Heini in February.

Meanwhile, Netto MD Richard Lancaster stepped down in November 2008 ­after less than two years and was ­replaced by Charles Kay.