The transition from rule-based to neural-based architectures has made it more difficult for low-resource languages like Scottish Gaelic to participate in modern language technologies. The performance of deep-learning approaches correlates with the availability of training data, and low-resource languages have limited data reserves by definition. Historical and non-standard orthographic texts could be used to supplement training data, but manual conversion of these texts is expensive and time-consuming. This paper describes the development of a neural-based orthographic standardisation system for Scottish Gaelic and compares it to an earlier rule-based system. The best performance yielded a precision of 93.92, a recall of 92.20 and a word error rate of 11.01. This was obtained using a transformer- based mixed teacher model which was trained with augmented data.