@cre8toruk : if you a have a Windows PC somewhere on your pfSense LAN network, check out :https://github.com/KoenZomers/pfSenseBackup
Just set up a daily task that downloads the complete config.xml.
You could retain the last 30 or 60 files (= 2 months)
When you need to use your spare pfSense box, fire it up, import the latests backup, and your ok.
No USB drive needed.
Normally, no more need to think about it.
Just, ones in a while, check if the daily backup is made.
I'm using this backup tool for years now, and have always the latest 60 days / config.xml locally available.