Here are some limitations that affected me:-
Only defined contribution, defined benefit pension schemes and SSAS can be transferred abroad.
UK state pensions cannot be transferred.
The rules also state:-
I wonder if Brexit will have impacts?.........be established in a Member State of the European Union, Norway, Liechtenstein or Iceland, India, and the United States.........
.........be established in a country or territory with which the UK has a Double Taxation Agreement (DTA) that contains exchange of information and non-discrimination provisions - see the list in RPSM14101046......