I don't think I understand your point. If you wired a ring in 4mm² cable and then cut one of the return legs, you'd have a radial with at least the same (current supplying) capabilities as the ring had, without any need for having any "bits hanging off it and wandering away in strange directions". Eric would probably warn that one could run into problems with Zs and/or VD with a radial, but I think he must deal with very long circuits<a repeat of what he wrote in his previous message>
Kind Regards, John