Rather than repeatedly having to identity the post code, add an AFTER INSERT, UPDATE trigger that finds the post code and then store its byte location and length in a column(s). Then you can quickly and easily upper-case the post code after the entire thing has been proper-cased.
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".