The deal sees the British Growth Fund (BGF) selling its minority stake in Brownhills, bought for £2.9m in 2015 to support its acquisition of Peterlee Glass in Durham.
Brownhills Glass is part of a group made up of the UK's leading independent glass merchants and processors, established in the 1970s.
As Duke's fourth European royalty partner, this broadens its revenue base
Duke closed on an initial commitment of £6.5m, with a further option for up to £1m until the end of 2019.
Brownhills has drawn down the funds and used the proceeds to refinance most of its outstanding debt and to complete the buyout of the remaining 70 per cent equity stake of an operating subsidiary Tufwell Glass in Crawley.
Brownhills now has 130 employees across three UK plants – the others are Brownhills Glass and North East-based Peterlee Glass – and is majority owned and managed by a family which has owned the group for a number of years.
Mark Harrison, group managing director of Brownhills, said: "The main attraction for choosing Duke as our new financing partner was the long term participating nature of its capital. At Brownhills, we have a clear plan to grow both organically and via acquisition and we are happy to have a supportive and aligned financing partner in place for the long term."
Chelverton Asset Management sold Tufwell, which launched in 2013, to Brownhills Investments for an undisclosed sum. In 2014 it was Chelverton Investor Club’s first acquisition.
Tufwell is one of the South East’s leading glass processing companies and has grown consistently under the Investor Club ownership and the leadership of managing director Andrew Maslin. Brownhills was a minority shareholder alongside Chelverton at the time of the original acquisition.
Chelverton Investment director, Richard Bucknell, who led the initial investment transaction and the recent exit, on behalf of members of Chelverton Investor Club, said: “Tufwell was a classic example of a Chelverton transaction; a good quality, consistently profitable business, with a strong and defensible market position. It has been a pleasure to work with Andrew and Brownhills over the last four years and we feel certain that the business will continue to go from strength to strength under the new ownership."