I looked at the sound regulations several years ago.
I seem to remember that the new sound regulations were going to make it compulsory for all new builds to have an acoustic sound test; but, they received such a backlash from the housebuilders that a messy compromise was hashed out. Basically a new standard was set that builders had to follow, the acoustic test was scrapped.
However, I also seem to recall that conversions were still required to have an acoustic sound test. Recent conversions therefore may prove of interest to you. You should be able to ask to see the acoustic sound test report.
If you would like more information, there is a good section in "The Housbuilders Bible" by Mark Brinkley. Pop in any good local book store and have a quick read