Steve Matthews
A carpenter would be a good category, as the work will probably involve fixing an insulated board material to a wall, and carpenters do dry lining. However you will need to find out if he/she knows about sound insulation. Ie how sound travels, as if you use the wrong method of fixings you will make a path for sound waves to vibrate through the material and defeat the object of sound insulation. This is called bridging. Part of my carpentry and joinery apprenticeship in the 70s and City & Guilds was Building Science, which covered sound, heat, damp, insect and fungus issues in dwellings. So look for a trader who is actually qualified, not a jobbing handyman who's joined Rated People. And importantly be specific with your job description. If you know the materials your going to use, find out from the supplier/manufacturer first how it SHOULD be fitted, and then question prospective carpenters how they would fit it. Hope this helps Steve I'm in Kent and really only work in Kent, Surrey & Sussex, but happy to quote if that's your area.
