There have been some temp corrn tables produced in the latest DAP amendment (126). Page DAP1-1 and DAP2-2/3 refer. It is my understanding that these tables are the precursor to an AIP amendment to follow in June requiring temp corrn to be applied when forecast aerodrome temps are below ISA -5.....thats all I know. Guess we will have to wait until June for the comprehensive guidance to be published.
In the meantime, you might want to familiarise yourself with the tables.