I don't think I can fix it. Already has a hardcoat over them.
I was aware that they might need to be fitted horizontally, but the Tamiya decals I had and the decaling instructions did not include these LG stripes. the ones I had were from Hasegawa, and the flashes just a fraction too wide for the gear. Certainly I could have fitted then trimmed, but just assumed they were supposed be fitted vertically.
Cranky with myself that I got that bit wrong. I have to live with it now I think, unless I get replacement flashes to fix it.