Hi Glen and Group,
The breakout board is not required as the back panel inside has the required circuitry to interface to a HR50. You just have to do some point to point wiring to the DB9 connector.
Thanks Mooneer for offering to send your extra boards. It is economical (<$2.00) to send a small unpopulated PCB to the UK if you use a stiff cardboard envelope, the type used for pictures, and send it from a USPS automated kiosk. Mark it as not rigid.
For those interested in the extra IO boards, the idea is that you can have the boards you want made. The gerber files ready to be sent to the PCB house are available on github. See
www.pcbshopper.com for places that will build boards. Often JLCPCB offers a $2 special for new customers.
73,
Steve
kf7o