Can't get Allo Relay Attenuator to work

I’ve uploaded an error log -
My config is a Raspberry Pi 3B+ with an Allo Digi One feeding my DAC. Been working fine for a while.

I am now trying to get an Allo Relay Attenuator connected “offboard” using an RPi breakout to feed the needed 5v, ground and 3 signal lines (SDA on J7 of ARA goes to RPi SDA1-12C which is pin 3, SCK on J7 of ARA goes to RPi SCL1-12c which is pin 5, and GPIOB15 on ARA goes to RPi pin 10).

I want the ARA to sit in between DAC and Preamp so that I have digital control of volume via hardware mixer from Volumio.
I’ve installed the Allo Relay Attenuator plugin, but I don’t see the option in the playback menu to select hardware volume control.
Further info - I’m using BruteFIR for DRC (which is also working fine).

Looking at the data/plugin/miscellanea directory on my RPi I see a file npm-debug.log which contains the following error at the end (I can upload the entire file if helpful) -
138 error file /home/volumio/.npm/kew/0.7.0/package/package.json
139 error code EJSONPARSE
140 error Failed to parse json
140 error No data, empty input at 1:1
140 error
140 error ^
141 error File: /home/volumio/.npm/kew/0.7.0/package/package.json
142 error Failed to parse package.json data.
142 error package.json must be actual JSON, not just JavaScript.
142 error
142 error This is not a bug in npm.
142 error Tell the package author to fix their package.json file. JSON.parse

Any advice would be much appreciated.