First quarter like-for-like sales at pub chain JD Wetherspoon increased 1.6% while total sales in the period rose 7.3%."Our sales, profit and cashflow continue to be resilient and the performance of our recently opened pubs remains encouraging," the group said in today's quarterly update.There had been concern over Wetherspoon's quarterly update after October's surprise announcement of the departure of its finance director and chief operating officer.Rumours of a boardroom bust-up quickly followed. No explanation was given so speculation circled around a disagreement over the rate of the group's expansion strategy or a disagreement on whether to invest cost savings to protect margins. In today's statement Wetherspoon said its planned investment in till systems, pub refurbishment, pub staffing and support has resulted in an operating margin of about 9.4%, around 0.7% lower than the same period last year and in line with company targets. "We are targeting some margin improvement in the second half of this financial year," the group said. The group previously warned first half profits would be hurt by higher interest charges, following refinancing in March 2010. However the company remains, "confident of a reasonable outcome for the year as a whole, helped by investments in new and existing pubs."