In the Training Com of Autumn 2019, the CAA gave instructors guidance on what to include in the Refresher Flight Training for the revalidation of the SEP rating
TrainingComUpdateAutumn2019(CAP1860).pdf (caa.co.uk) They quote CASA data that a partial failure it three times more likely that a complete failure
https://www.atsb.gov.au/publications...-3-ar-2010-055 and suggest this is covered in the RFT. And in my experience of two engine failures in single engine aircraft both being partial, confirms this to me. I have always included the partial failure in PPL instruction training and I make all the simulated failures for my currently/revalidations partial ones. I get interesting responses, even if they were pre-briefed. Most PPLs haven't been trained for this, only knowing the complete failure scenario and most haven't even considered it having being only exposed to any engine problem leading to a PFL. Mandatory inclusion of this in the syllabus is long overdue in my opinion.