I have found some more info which is still confusing.
Seychelles has a TIN number which is a 9 digit number which is randomly generated by an algorithm which also ensures that it meets a checksum requirement. so they can verify it. Nonetheless
Seychelles indicates that IBC are not issued with a TIN number.
Furthermore, a clarification needs to be brought with regards to the International Business Companies (IBC) incorporated under the International Business Companies Act, 2016, Foundations as established under the Foundation Act, 2003 and Trust established under the International Trust Act, 1994. These persons are by law exempted from tax in the
Seychelles and consequently are not issued with a TIN by the
Seychelles Revenue Commission. These persons are issued with incorporation or registration numbers allocated to them by the Financial Services Authority. That would be the number generally used to identify them in
Seychelles by the agencies which will need to.
Not issued with a TIN
(1) International Business Companies (IBC) incorporated under International Business Companies Act 2016
(2) Foundations established under Foundation Act 2003
(3) Trust established under International Trust Act 1994
HK IRD states in their CRS exchange info :
Some jurisdictions do not issue a TIN, or do not issue a TIN to all residents, and where no TIN has been issued there will be nothing to report unless they use other high integrity numbers with an equivalent level of identification.
For entities, jurisdictions may use a business/company registration code or number where no TIN has been issued.
Some jurisdictions that issue TINs have domestic law that does not require the collection of the TIN for domestic reporting purposes. In such cases the reporting financial institution is not required to collect the TIN for those jurisdictions.
So perhaps just the BR number would be enough, still looking for people who have more experience with this