This isn't a BCC blast. Each client receives their own copy, rendered with their own details. Write {{ Client.Name }} once and every recipient sees their company name; the same goes for contact names, reference numbers, statutory dates, and any other client data you can insert as a token.
Compose the email from scratch in the familiar composer, or start from one of your reusable content blocks and tweak it for this send. Either way, you see exactly what you're sending before it goes anywhere.
