Thanks for the comments. I wasn't sure how people would respond to the flare (i did snap some without).
Btw, this was with the Ricoh GR, and that lens is really well behaved against light – I partly shielded the lens from the just out of frame sun wih my hand, opening my fingers a bit for the streaming effect. The only times I've seen unavoidable artifacts has been with the ND filter on in a sunset shot, it seems to add a little internal reflection to the system.
This was definitely a moment when I wished I had a unicorn or other suitable fairy creature handy. May need to go back with someone to put in front.