Is that the brand new roamer 230ah?
If so, that comes with built in CAN communication with Victron GX devices.
Just a thought... Ignore if you want...
The Shunt (£80) isn't needed if you were to get a Cerbo GX (£180) with BMS-CAN input, as it'll send the SOC directly from the battery to the Cerbo GX. You'll also need the Roamer cables, and VE direct cables for your Orion and MPPT so a few extra quid there.
However, what this would give you, if you've got a 4g connection in your van, is complete monitoring of your system from anywhere with internet via your phone, the ability to add Bluetooth or wired temperature and tank sensors, set relays based on various triggers, a full colour touch display, and so on...
It's little things like not having to be within Bluetooth range to check your solar output or battery charge level...
(180w at the moment on mine)
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You might not care about that level of monitoring but I thought you'd like to be aware of the options, as you can do without the shunt if you went this way.