Hi Guy!
I got emails once their system showed that they had received my documents, when it was approved and then printed. I sent my documents on 26th Feb and they were received per the Royal Mail tracking on 1st March but the system didn’t update them as being received until 9th March. I had an email on 19th March to say that my passport had been printed but only received TNT tracking this morning and was delivered the same day. Hope that helps! It does seem to be a very random and variable process, I hope you get yours sorted soon