POAT & GWRoB - No action ever taken

The taxpayer, now deceased, created a long lease (999 years) over her freehold London property in July 1997 with a long deferred lease start date to begin July 2027. The taxpayer died January 2021.
I am making enquiries with HMRC as to whether POAT was paid or an election made to opt into the GWRoB provisions after the POAT rules were first introduced.
I wonder how practitioners are dealing with the situation where the taxpayer never took any action in respect of either POAT or the GWRoB election?
Further, do practitioners agree that whether POAT or GWRoB applies, there is now a very significant capital gain in the delayed lease interest, because neither POAT or GWRoB rebases the asset at death?
Kurt Lee
Lester Aldridge LLP Solicitors

Yes, agreed. The base cost for CGT of the deferred lease is minimal (due to length of time prior to commencement). However, its MV will have increased through time as the day of the commencement of the lease draws closer.

The person entitled to the deferred lease will not be entitled to 100% PPR relief on any future disposal. Any CGT uplift wrt the freehold is likely to be minimal (or possibly nil).

I will leave others to comment on the other issues raised.

Malcolm Finney