[Koha] How to import loans data into Koha?

[Chris Brown]

Gentle Reader,

We are migrating records from a few small community libraries (currently
held as a fancy spreadsheet) into Koha 17.05. I have figured out how to
migrate the biblio records, items and patron data but I was wondering if
there is a way to import data on current issues (loans)?  All we really
need to import is the item ID, the patron ID and the due-back date.

Is there a tool to do this? Or is it a question of populating the issues
table directly? If so, does anyone have a script to do this?

Any pointers gratefully received ...

Chris Brown