Dictation behaviour with spaces and sentence starts

I have been using dictation for several months now with great success. Its behaviour has suddenly changed. It now insists on placing a space before every sentence, thus indenting the first sentence of each paragraph by one space, and defaulting to putting a double space between sentences; which I do not like. Further, the double space is often applied if I print whilst pausing for thought, mid-sentence.

Has anyone else noticed this change in behaviour?

I could not swear, but I suspect that it was triggered when I turned dictation off in system preferences, at that point not realising that this reset my cache on the server. Having said that, even when I first started using this system several months ago, it never did this.

I have since tried toggling dictation off then on, and also trashing the relevant preferences:

com.apple.speech.recognition.AppleSpeechRecognition.prefs

com.apple.speech.recognition.feedback.prefs

com.apple.speech.recognition.recognizer.prefs

Does anyone have any thoughts or ideas around this?

[In this post, I have left the one space paragraph indentations, but had to manually delete those between my sentences and clauses.]

Best regards,

Justin