if you did carry out a perfectly legal PFL in most of the UK down to 1' you would likely be guilty of "recklessly or negligently acting in a manner likely to endanger an aircraft or any person in an aircraft".
With profound sympathy for all of the regulatory self-flagellators on this forum and for the few CAA refuseniks who are striving to undermine their Chief Executive, but Andrew Haines put paid to that particular birch twig two years ago with Question 5 of CAP 1188...