Theo Paphitis has strengthened his senior management team across his Ryman, Boux Avenue and newly acquired Robert Dyas brands.

The Dragons’ Den star has appointed Richard Bennett as chief operating officer for Ryman and Nadine Jones as group HR director across Ryman, Boux Avenue and Robert Dyas.

Bennett will report to group chief executive Kypros Kyprianou who in turn works across all of Paphitis’ commercial interests. Bennett was retail director at Spar UK and prior to that worked for 18 years in a variety of roles at Marks & Spencer.

He will lead the stationery chain’s buying, marketing, store operations, logistics ecommerce and B2B functions.

Jones joins from a role as HR director at jewellers Links of London, and has previously worked as head of HR for Baugur Group, Austin Reed Group and Asda. She will also assist Paphitis as project director.

Paphitis said: “It is crucial that my businesses have the best talent in the industry. As well as developing the 3,600-plus work force, I have invested in two new high level appointments to help drive the businesses to the next level.

“Retail is facing the greatest challenges seen since the industrial revolution. Only retail businesses with a meaningful proposition and excellent customer service have a chance of survival in the long term.”

Paphitis bought Robert Dyas’ 96 shops earlier this month for £10m to add to a varied empire of businesses worth £210m.

Boux Avenue opened its first shop in Glasgow last April and now operates 12 stores across the UK. It aims to boost store numbers to 18 by Christmas. Internationally the lingerie retailer has laid out plans to open up to 30 global stores by the end of next year.

Sister company Ryman posted a rise in pre-tax profits earlier this year, thanks to an expanded range and growing website sales. Pre-tax profits rose 14.1% to £7.2m in the year to April 2, 2011. Sales were up 2.3% to £126.2m.