UK exporters such as BPI Polythene are continuing to benefit from the weakness of sterling against the euro and are intensifying competition to win business on the continent.An interim statement from BPI revealed a continuation of an uptick in orders that began in July and was sustained through the third quarter of the year.The group attributed its stronger sales to the weak exchange rate between the pound and the single currency, which approached parity earlier this year.However, the BPI added that there has been a concomitant rise in material costs due to the weak exchange rate."Our raw material costs have risen in the last few months, but are now looking to stabilise or erode very slowly. We are fairly well hedged against this winter's power costs, both in the UK and Europe," the interim statement declared.For net-importing companies or those who handle large volumes of international business transactions, the weak exchange rates witnessed in the last few months may make seeking out the best foreign exchange deals particularly important.