When did you send the emails? July-Sept tends to be a difficult time to get hold of academics - as well as holidays it's conference season, supervision time for MSc students and preparation time for the start of the new academic year. So people might not be on top of their emails.
I'd caution against sending unsolicited research proposals. At best they may be ignored by busy professors; at worst your might find your ideas being pilfered.
I'm a little unsure from your post whether you have actually applied for a formal MRes programme. Usually there would be no need to approach supervisors directly in advance.