I have a retired relative in a similiar situation.
Approximate figures. PPR worth 700k+, mortgage nearly paid off.
Rental A worth 400k. 200k outstanding on interest only.
Rental B worth 400k, 200k outstanding on interest only.
Rental C worth 375k, 200k outstanding on interest only.
Rental D worth 400K, mortgage outstanding mortgage 590k (bought in 2006, pre 2008 crash, a bad decision).
Rentals A, B and C have two years to run.
Rental D has a longer term around 4 years.
Plan is to sell the PPR. Issue notice to a tenant. Move into either A, B or C, pay off all three mortgages with PPR. Avoid CGT. Keep 2 rentals. But the problem down the road is D. I assume getting deeds on A, B and C will be doable ? But perhaps not ? What is lender likely to request on redemptions of A, B and C?