Not so! Check the ANO. The restrictions on flight training from unlicensed aerodromes apply to:
(iii) flights for the purpose of:
(aa) instruction in flying given to any person for the purpose of becoming qualified for the grant of a pilot’s licence or the inclusion of an aircraft rating, a night rating or a night qualification in a licence; or
(bb) a flying test in respect of the grant of a pilot’s licence or the inclusion of an aircraft rating, a night rating or a night qualification in a licence
Flight Instructor Ratings, IMC Ratings, SEP Revalidations or Renewals are therefore permitted, in my view, because they do not fall into para (bb) above. Neither does 'differences training'.