Re registering smart key after changing secondary suse box

[Kebablover]

Afternoon all. I purchased a S/H secondary fusebox with a view to fixing a central locking issue  (located behind the glove box). The good news is that my central locking now works again but only with a physical key. I can't get the proximity key to pair back with the locks. As there is no lock barrel in my 2010 Avensis (it is push button start only), I cant try any of the pairing fixes listed on the forum. I have various versions of Techstream but non have the Avensis listed in the drop downs. My knowledge of Techstream is very limited and I dont want to try and reprogram the keys in case I lose the ability to start the vehicle. There is the nagging feeling at the back of my mind that the ECU in the replacement fusebox may be at fault but I am not prepared to pay for a new one at £700 for a car that is 10 years old. Can anyone offer advice please?