New build, stressful process, ~12 months back, but finally working like a dream. The reporting/modelling/strategy was done independently, then the MVHR and ducting was ordered/commissioned via Green Building Store. We should have gone with the latter for everything to make things easier.
We originally planned sound reduction strategies and an MVHR installation on the first floor, but supposedly it wouldn't work well for a timber frame build where the floors act like drum skins (even with shock absorbers). Switched to ground floor after some advice/site visits and now have a completely silent install (but no equivalent to compare it to).
Also have SunAmp PV units for hot water which are amazing (removing the thermal store helped us to avoid over-heating in summer).