Comparative & general (ie not single country specific) commentary have shelf marks - Legal Hist or Cw Gen or General. All three collections are shelved on Level 2, the entrance level of the Law Library
A bibliography of the law of British colonies, protectorates and mandated territories : being volume VII of Sweet &Maxwell's legal bibliography at Ref Bibl Cw UK M464/7
There are two general subject searches to use in SOLO
Law -- Great Britain -- Colonies -- History;
Law -- Commonwealth countries -- History
Or look for works on single jurisdictions by constructing subject searches following example below:
Law -- Australia - History
The following jurisdiction guides have a page looking at the nation's legal history: