[Koha] a sticky puzzle

[Chris Meech]

Hi all,
I've got trouble with a phantom itype that can't be deleted. When I try to delete it from the client I get this notice:
Cannot delete item type
This record is used 1 times. Deletion is not possible.
But I can't find where is this itype being used?

mysql> select * from items where items.itype='PUZZ';
Empty set (0.00 sec)

Any ideas or suggestions are appreciated.
Koha version:

3.14.04.000


Cheers
Chris