Hi, the will is as you say registered in the UK.
FERGUSON Albert David of 50 East Johnson-street Philadelphia
State of Pennsylvania U.S.A. died 26 November 1946 at
Temple University Hospital Broad and Ontario Streets Phila
delphia Administration (with Will) (limited) London 8 August
to Guaranty Executor and Trustee Company Limited attorney
of Charles Frederick Miller, Lulu Marie Miller spinster and
The Girard Trust Company..
Effects £13849 3s. id. in England.
Ancestry UK has PCC wills and others that records offices have put online but from 1858 it has the National index which is also freely available from the government website. You can purchase a copy of the will from there. https://probatesearch.service.gov.uk/Calendar#calendar