I'm not accepting the "nobody buys a golf between september and december"... I mean that has been their launch time every time...
There's something else here, but quite what I don't know.
Plus if you don't use the downtime in August to retool then you are wasting production time which costs them £££££
Then factor in that everyone knows the Mk8 is coming so won't buy a Mk7.5 anyway...
They know this, VW will fully understand the financial impact and so they'll only do it if there is a very very good reason... which has to be technical in some way shape or form.