IHTM14514 - Lifetime transfers: the charge to tax: potentially exempt transfers (PETs): cumulating transfers more than seven years before death
As in the previous cumulation example (IHTM14513), you may have to look back at transfers more than seven years before the date of death, and possibly up to 14 years. For instance, where a PET was made 6 years 11 months before the death you will need to consider the period 13 years 11 months prior to the death.
In practice, you only need to look for transfers outside of seven years of the death which were immediately chargeable, such as a transfer into trust.