Our head office is in London and we have a regional branch in Dubai.
This compound sentence has an error known as fused sentence.
https://webapps.towson.edu/ows/sentelmt.aspx#comma%20splices
Error #2: The Fused Sentence
Writers make this error by joining two independent clauses into a compound sentence without using any punctuation between them.
No punctuation between the two independent clauses causes them to "fuse" into an INCORRECT compound sentence.
We can repair that by adding a comma before the coordinating conjunction, replacing the coordinating conjunction with a semi colon, or using a conjunctive adverb with a semi colon and comma.
Our head office is in London[,] and we have a regional branch in Dubai.
Our head office is in London[;] we have a regional branch in Dubai.
Our head office is in London[; also,] we have a regional branch in Dubai.