Pilot trusts and subsequent business transfers

 

What are peoples opinion on the following. Settlor has a full NRB available and establishes 10 pilot trusts. 3 years later, the same settlor established a new RPT with a £100k of property qualifying for 100% BPR. Settlor dies in year 6 dropping property into the pilot trusts.  The property transferred in year 3 no longer qualifies for BPR. I appreciate the add back of BPR for the transfer to the RPT trust in year 3 but, does this affect the nil band for the pilot trusts when computing occasions of charge for IHT?   I understand add backs of BPR ordinarily on CLTs do not normally affect the cumulative carry forward in computing the NRB available to the estate but, does it still become a gross chargeable transfer in the 7 years pre addition to the pilot trusts?