This would be the main reference book to check that the results of your EICR are correct and the readings are within tabulated parameters, any issues found with your certificate would be highlighted with reference to this electrical publication.
This would also be used for reference which details the correct testing procedures for electrical installations, some test procedures should be carried out in sequence within the stated order.
This publication also provides a guide for technical issues and also expands on procedures that are not present in the BS 7671 regulations, it is expected any operative working to this guide will be competent to do so.