Some handy links (note: each link opens a new tab)

DescriptionLink
Building Regulations
Part B of the Building Regulations - Fire SafetyBuilding Regs Part B
Part F of the Building Regs - VentilationBuilding Regs Part F
Part L of the Building Regs - Conservation of fuel and powerBuilding Regs Part L
Guidance Documents
BPEC Guide for domestic ventilationBPEC Guide
NHBC Guidance 2017 - Chapter 8.3 Mechanical Ventilation Heat RecoveryNHBC website
NHBC Guidance 2017 - Chapter 8.1 Internal ServicesNHBC website
CIBSE Domestic Heating GuideCIBSE Guide
CIBSE Plumbing Engineering Services Design GuideCIBSE Design Guide
Controls
HoneywellHoneywell
DanfossDanfoss
HeatmiserHeatmiser
Installation Checklists
SAP Requirements - AllSAP checklist
MVHRMVHR Checklist
MEVMEV Checklist
WWHRWWHR Checklist
Further reading
National Custom & Self Build AssociationNational Self-Build Association