Harold Cottam, who took over as non-executive chairman last September, said he would be taking on a more executive role in Haden in conjunction with Richard Taylor and Clive Mayhead, managing directors.
This process had already begun and had left Mr Hawley as 'the piggy in the middle', according to Mr Cottam, a former UK managing partner at Ernst & Young.
To reassure investors that no black hole has been discovered Mr Cottam said trading was in line with expectations and the company had positive cash balances following the sale of its Spaldings agricultural parts distributor to management in December.
He described the departure of Mr Hawley, who was promoted from managing director to chief executive only last April, as amicable. Mr Hawley has a rolling two- year service agreement.
Management was strengthened last October when Ken Dargatz joined from GM's paints facilities division. There were also plans to boost the team by appointing a finance director, Mr Cottam said.
Haden MacLennan, which makes vandal-proof toilets and automated manufacturing systems, was formed in 1987 from a reverse takeover of P&W MacLennan by the unlisted Haden and Haleworth Holdings.
Haden shares rose from an initial 150p to a high of 257p in 1989, but there was a collapse to a low of 23.5p last November in the wake of poor interim figures and a slashed dividend. The shares closed 1.5p lower at 41p yesterday.