Would this not be a complaint better aimed at the council? Isn't it an anti social behaviour issue?
I think of myself as pretty live-and-let-live and feel like a miserable cow for saying this, but I do think I might complain. Personally I love the sound of fireworks but our dog is under the table, shaking like a leaf night after night and collapses in the street when he hears the noise. I'm worried his heart'll give out.
Have you complained to the solicitor directly and did they respond within the 8 weeks they have under their code of conduct - I presume they have and this is why you have escalated further to the SRA? If he doesn't respond in a timely fashion per the SRA code of conduct then I am sure they will need to take action.