Asos, which today reported a healthy 20% increase in overall retail sales for its third quarter, said the upgrade of its supporting IT infrastructure is making good progress.

"IT replatforming is a continual process – a bit like painting the Forth Bridge," said Asos CFO Nick Beighton. "So we should never stop enhancing our technology."

The online fashion giant is replacing its current IT infrastructure to support its underlying sales ambitions to become a £2.5 billion business. The replatforming is being headed up by the new CIO, Clifford Cohen, who was hired in February to replace Pete Marsden.

Beighton said the IT replatforming – which covers several areas of the business and will help Asos increase its volume – will aid the retailer as it prepares for Black Friday.

"Last year we were one of the few retailers which managed to get the majority of our orders in place to our customers and didn't have any site outages," Beighton told Essential Retail. "And we are prepping on that solid foundation to have the exactly the same sort of response for our customers. Some of that will be part of the tactical work and some of it will be part of the replatforming work which is well in place for Black Friday and beyond."

Asos today reported its third quarter results, revealing a 20% increase in total retail sales to £386 million. UK sales climbed 27% to £158.4 million, while international retail sales (which now accounts for 59% of total sales) increased 16% to £227.6 million for its four months to 30 June 2015.

The fashion e-tailer also said it now has 9.7 million active customers, an increase of 11% year-on-year. And Asos customers are spending more money and ordering more frequently, while mobile and smartphone now accounts for 60% of traffic to Asos.com.

The third quarter results will come as good news to CEO Nick Robertson who had a difficult 2014 consisting of profit warnings and a fire at its Barnsley warehouse.

Solving the problem of online returns

But strong performance from the UK and Germany is having a knock-on effect on returns which Robertson said are edging higher.

Robertson said the retailer is always on the lookout for new technology to help customers select the right size online. "Not least because of the returns rate, but the customer satisfaction point of view – none of us like to have to go through the process of returning," he said.

"The business is constantly looking at ways to improve the service and inherent in that is free returns."

But the Asos boss has yet to find the perfect solution.

"There are none on the market which are robust enough to make a dent," he added. "We've looked at a number of solutions over the years, but none of which are leaping out as a good or satisfactory customer proposition."