The variations I've seen in print:
Hxno A123456-7 SMC, A0, A3, A9, A11,
Hxno A123456 - 7 A5
Hxno A123456 7 S3, S10, A6, A7, A10, A12, A13, JG-LS, JG-MA, JG-CM, JG-GR
Hxno-A123456-7 A0, A1, A2, A3, A11,
Hxno-A123456 7 A4
A123456 Hxno JG-CR
A 123456 Hxno JG-LS
A 123456 Hxno JG-CM
A 123456 7 Hxno JG-MA JG-CM
Hxno A123 456 7 JG-MA JG-CM
Italics indicate may not be seen as part of UWP, bold indicates clearly part of UWP.
My preference is the double dash, and like Robject, I think the triple dash useful.