The key point to make about testing according to E1 of the building regulations is that it is only between two dwellings. It therefore is not suitable for homeowners of new build houses that e.g. have creaking floorboards from their own bedroom to downstairs lounge (as the most common complaint we hear about!). This is because the building regulations to do not have a pass rate for this from a field testing point of view. The detail of how walls and floor types should be constructed is specified in Section 2 of part E. An example image of this is shown here.
Also when carrying out the field tests, they are done per property type. So on a large site, the builder will not have to carry out the test on every property with an adjacent property (town house, semi detached, apartment etc). They rather just need to carry out this test on each grouping type and assume the others of the same grouping will be the same result.