Below occurs on both Zorin Light and Mint xfce.
Have removed all added-on Brother drivers on both computers.
Have also uninstalled xsane and the sane-utility drivers from Zorin.
Printing
Both Brother MFCs will print from the support in the Linux (?)kernel - without the additional drivers from Brother.
Scanning
Both Brother MFCs will do single page scans from the flatbed using from the support in the Linux (?)kernel which provides the ESCL options in Simple Scanner / Document Scanner.
Neither will do multi-page scans using the ESCL option.
Summary
There seems to be conflicts between the built-in Linux drivers and the ones provided by Brother. Removing the ones from the Brother website allows printing and very restricted scanning to occur.
Next step
Have found I cannot print or scan via USB on Debian 11 or later, Ubuntu 20.04 or later and on their derivatives (Linux) | Brother
Just need to carry a 50lb printer down some stairs to try this out.
[REDACTED]
Oh goody, I love IT, something for another happy day.