A list of organisations certified by one of CREST's Member Companies is available here.
If you are unable to find the organisation you are looking for, please check whether the organisation was issued a certificate by a CREST Certifying Body (the Certificate will contain the CREST logo if it was issued by our of our CBs), and if so you can enter the certificate number on the CREST Cyber Essentials Certificate verification page.
CREST operates alongside other UK Government approved Accreditation Bodies. If the certificate was issued by a Certifying Body under one of the other Accreditation Bodies, you can carry out a validity search on the NCSC website here. Please note that the NCSC website only lists those certificates that have been issued within the previous 12 months.