ID carrier / ID correct file to downgrade baseband

[Tom5000]

hello, I would like to unlock my s4 mini (GT-I9195) can anyone help with two problems:

1. I need to figure out what carrier I am on (someone gave it to me without a sim)
2. I am trying to use 'galaxsim unlock' on playstore. It rooted the phone but says 'your device should be unlockable if you downgrade you baseband to MJ7 or before'.

Can anyone point me to the correct .tar file to load into Odin to do this?

pastebin of screenshot here
thanks.
Tom

 

[Tom5000]

UPDATE: OK, so have ID'd network (EE in the UK) and paid them for unlocking, however, it failed and they are trying to contact Samsung which may take 10 days.
I wonder if I can do this myself - just need the correct file (baseband) to flash.

If someone can point me to it that would be good.
(I think this may be it, although I'd prefer not to pay if possible:
https://www.sammobile.com/firmwares/galaxy-s4-mini/GT-I9195/EVR/download/I9195XXUAMF5/16156/)

thanks