Horvath is to take on the role of group managing director.
David Lawther, a former finance director with Wilson Connolly, will take over as head of finance.
The group said results for the year to 30 June would be in line with expectations. House broker Collins Stewart is forecasting a pre-tax profit of £6.8m.
Pre-tax profit rose 35% to £3.57m for the six months to 31 December.