Can you come up with a risk-assessment method that would justify applying a low-risk status for the suppliers?
It's unusual for BRC to be so forthright about your risk assessment, as whilst auditors always have their own view it is your business and your suppliers so as long as you can justify what you're doing it should be sufficient. Obviously life would be easier for all concerned if they were GFSI certified, but it's not always possible in the real world.
What currently factors into your risk assessment for the suppliers?
If it's just certification standards then absence of GFSI will obviously be a challenge, but for example we also use the following in the supplier risk assessment process:
Other certification (e.g. ISO9001 - not much help from a food safety perspective, but it does at least show some commitment to management of systems)
Size of supply - if you buy a lot then the risk/exposure is potentially greater
Transparency index for the country in which the supplier is located - based on Transparency International's Corruption Perceptions Index
Location weighting
Historical relationship - a long trading history with no problems should reasonably be assumed to indicate a lower risk
Maybe you can use something like these to come up with a more substantial justification for the low risk status? (assuming you genuinely think they are low risk sources!)
It looks like clause 3.5.1.2 is going to be modified in Issue 8 (at least based on the last draft consultation I saw) but still has the option for SAQ for low risk - just makes it a bit clearer what is required in terms of justification via risk assessment, but still very much up to the individual business to determine what "low risk" means.