Here’s another cite from a British Police Force guidelines
1.2.7 Witness Statements
The declaration at the top of the MG11, must be written out by the interpreter in the relevant language, signed by the person making the statement (not the interpreter) and the signature witnessed. The person witnessing the signature will normally be the interpreter.
The officer will then gather the witness’ evidence in the usual manner by questioning the witness through the interpreter. The interpreter should then write down the statement on an MG11, in the witness’s own language, in the witnesses own words as guided by the officer. This record is called ‘the original statement’. The role of the officer is to ensure that the statement is factually and evidentially correct.
Once the witness statement is recorded in the other language, the interpreter will make an English translation of that statement on another form MG11. This translation is an exhibit. The interpreter must then make another witness statement in which they explain how they were employed to write down the statement and produce the English translation as an exhibit.
Is this what happened in Portugal in 2007?