The fully air conditioned Royal New Zealand Navy "Rothesay" class variant, , which gave all the crew a bunk and cafeteria messing and a RNZN Commissioned design study for a more fully capable Type 12 frigate, which also assessed whether the Type 12 could carry 2 of the larger Wessex AS helicopters, was used as the basis of the RN Leander Improved Type 12 design.