No, held the EAT in Mist v Derby Community NHS Trust.
The first Respondent was named correctly in the Claimant's ET1, but incorrectly on the Acas EC certificate. The second Respondent, which was joined at a later date, challenged the Claimant's compliance with the EC provisions. HHJ Eady QC rejected the second Respondent's arguments in relation to the EC provisions:
1) s18A ETA 1996 requires a Claimant to provide prescribed information to Acas. This includes the prospective Respondent's name, but not its full legal title. If relevant information is absent Acas may reject the notification or contact the Claimant to obtain any missing information. In this case Acas did not reject the notification and the employment tribunal was entitled to treat the EC certificate as conclusive in terms of the Claimant's compliance with s18A.
2) rule 12(2A) of the ET Rules 2013 provides that an Employment Judge can decide that a claim should not be rejected where there is a difference between the Respondent's details in the ET1 and the EC certificate.
3) as for the application to join the second Respondent, this fell to be considered as a possible amendment to an existing claim and did not require a further EC notification.