Now you got me wandering... was the time when English people knew Latin the best, because the rest of the world was still thinking the language(s) they were speaking was Latin (Meroveian Latin) before, or after the time of multiple prefixes?
Hmm... before, I think.
So you are right. It could come indirectly, through French.

Yes, they are very amusing. "If it is longer, it is more Latin." :-D