Company Reg Number on name reg cert?

Hi,

Getting our letterheads for our business done up at the moment. We are an unlimited partnership. Do we have to put the company reg no. on letterhead? If so, is this the number on the top left of our Certificate of Business Name registration?
Any help appreciated.

6 digit number at the top left of the cert, should start with a 3 i think.

otherwise a search [broken link removed] will tell you

brilliant, thanks!