As I recall, in NA2
Written by Mandy N
(9/17/2013 9:39 a.m.)
in consequence of the missive, John Thorpe, penned by Bridget D
... at the theatre John Thorpe tells General Tilney that Mr Allen had made a fortune in trade and has nobody but her (Catheine) to spend it on which brightened up the General.
John Thorpe is the only one to refer to a fortune from trade in the film but it's unclear whether it is a deliberate change on the part of AD or a deliberate lie by John Thorpe to show how unreliable he is.
This is just my take, on the point of Mr Allen's wealth, I don't see why John needs to lie as a fortune is a fortune and if it comes from land, surely old money sounds better and more impressive to General Tilney ?
In NA canon, John Thorpe does boost up Catherine as he wants to impress General Tilney. Catherine was already friends with the younger Tilneys and John hoped to marry Catherine as he believed the Morlands to be rich or, at least, he knew the childless Allens were rich. He knew Catherine was with them in Bath and saw they were kind to her, so John probably assumed she was heiress to their fortune because he wanted to.
I can't see why John would need to be mistaken about Mr Allen's status as a landowner.
As for the invisible mustache, apparently, it's in reverse to dea ex machina in the constructing the plot for a film. in other words, I'm also rather confused and prefer to wait for Adrian's explaination.