The expectation-maximisation (EM) algorithm has proven to be effective for a range of control-relevant estimation problems. Unfortunately, the way in which the EM algorithm is applied in this prior work has proven unsuitable for the commonly employed innovations form model structure. This paper addresses this problem, and presents a previously unexamined method of EM algorithm employment. The results are profiled, which indicate that a hybrid EM/gradient-search technique may in some cases outperform either a pure EM or a pure gradient-search based approach.