The group behind the challenge says it will now look to get a judicial review after raising more than £160,000 for it.
One of the three complainants, a woman from Hounslow, says she has already been harmed by 5G, suffering skin blisters.
She contacted Hounslow Council last year seeking information about 5G masts and radiation from street lights.
At the time, the council insisted there was no 5G equipment in the street lighting.