You may well be right, I have to say it was a pretty detailed application.
The two main thrusts being that proper grid references were required of where you would be fishing. This was apparently to ensure you were not operating in conservation areas known to still contain white claw crayfish but I also suspect it was, as you say to monitor the invasive signal crayfish population. The other was to ensure the trap was the correct size, they wanted mesh size, overall dimensions but most most crucially the aperture diameter so otters would not get trapped. There have been horror stories where otters have been found stuck in home made traps with half their faces eaten by the already captured crayfish.
I suspect the IA find it difficult in the present climate to issue licences because it’s not just an emailed licence, they also issue special licence tags to attach to nets etc. This would clearly be difficult to do with staff working at home but surely it’s an aspect that could dispense with until the pandemic issues ease and in the meantime email out licences once they were satisfied with the above mentioned criteria. The IA seem to be a pretty tech savvy bunch. As an example I even had to add my digital signature to the application form, it was pretty well designed in technical terms I have to say.