Could you please tell me if the phrase, "heard said", is acceptable. Such as-
"Cleft in chin, devil within", I've heard said before. For some reason, it doesn't sound right.
Yes, it's correct.
"I've heard "Cleft chin, devil within" [being] said before" is another way of putting it.
It's not a common construction. It's two past participles in a row. The first relates to the subject, and the second to the object. The second past participle can sometimes be seen as an adjective.
"I've heard this Mass sung before; This Mass I've heard sung before"
"She's seen many hearts broken; Many hearts she's seen broken."
Commonly, less formally, speakers avoid the two participles in a row by replacing the saying with an 'it': I've heard it said that.......; But there's nothing wrong with the shorter version.
b