I had a call with EST today and they needed verbally reconfirm that I was indeed purchasing the vehicle, etc.. This was then followed by yet another email to EST which confirmed this conversation - talking about OTT.
Anyway, they also said that they requested the Invoice Verification from Tesla. I contacted Tesla and the helpful sales guy at Tesla (who has been excellent, BTW) immediate responded and advised that Tesla has already verified this with EST. So, bar anything else needing reconfirmation, the funds should be approved any time and then could take another 5 days to reach my account.
Weird is that EST thought I could take delivery of the car and then pay the invoice. They seem to be living in a different universe, so had to walk them through the process and the deadline when I needed the funds in order to take delivery of the car at the end of the month.