If you look at JAR-FCL 1.005 (a) (2) it states that all licences ratings, authorisations and approvals mentioned in JAR-FCL are those issued in accordance with JAR-FCL. This therefore means examiners must be approved in accordance with JAR-FCL.
The examiner must hold an authorisation issued by a JAA State, in the UK this was initially achieved by existing examiners studying JAR-FCL and JAR-OPS and signing a declaration.
The UK will accept a SRG1119 signed by an examiner approved in other JAA States. Some States do not, it rather depends upon the laws of the State. If you download the form from the web, the examiner will complete it and either you or the examiner can send it to the address on the form.