Just wanted to say that I am in a similar situation and, having read your post above, have only now realised that 2 weeks may not be an accurate estimate.
I was wondering if there has been any news for you?
I cannot remember if I opted for secure delivery/return of my foreign passport when applying more than a month ago (was there such an option?), but checking TNT tracking website regularly using my PEX number and the only “consignment” showing up is the one related to the new passport itself (delivered). But nothing else (probably means Passport office haven’t sent any supporting documents back yet).