Leisure group Whitbread has issued another upbeat trading statement, posting continuing double-digit sales growth at its coffee shop chain Costa and a move into like-for-like sales growth at its hotel chain Premier Inn.In the three months to February 18, sales at Costa climbed by 19.9% from the same period the previous year as the coffee chain continues spreading across the country. Even without the impact of new openings, the chain saw strong growth, with like-for-like sales climbing by 9.5%.Sales growth at Premier Inn was more modest, climbing by 8.5%, or 1.7% on a like-for-like basis, the first time the chain has reported growth in like-for-like stores since the start of the downturn. The hotel chain has performed resiliently in a tough market, helped by Premier's value offering which includes rooms at £29 a night. The company said Premier had outperformed the market, with revenue per available room (Revpar, a key indicator of hotel groups' performance) down by 6.9% against a sector average of 10.2%.Sales at pub restaurants were up by 2.1% or 1.3% on a like-for-like basis. 'Whitbread's trading performance continues to be robust,' said chief executive Alan Parker, whose retirement was announced yesterday.Parker will step down from the UK's largest hotel and restaurant group on 25 November, his 64th birthday, after six years at the helm. He makes way for 52-year-old easyJet boss and former RAC chief Andy Harrison, who joins as chief executive designate on 1 September.