Just checked SD on my Mini 3 with my Bad Elf Pro+ and there are no issues with iOS 8.3 using that combo. Checked with both internal GPS off and then with both internal and external operating.
Bad Elf accuracy is 5m or better which is why I tend to prefer using this over the internal one and it prevents the occasional drop-out with the internal GPS, although never experienced it on my Mini but have on my full-size iPad 3.