Why go to the trouble of calling Gatwick when you could check the CAA website? The Brexit microsite will direct you to archived information published last year which describes UK recognition of EASA training with certain provisos, including tests, checks and assessments by EASA Instructors and Examiners, as well as FSTD qualification from 1st January 2021.You will bear responsibility for assuring the MCCI's acceptability for example, so suggest a call back to the ATO might be more useful.