Hard to maintain it's really not an option when it comes to working with databases, you got to do what you got to do. Data entered by users can be very tricky and whether you like it or not as a DBA your job is to maintain it, easy or difficult it's part of the job.

What you have to consider is what's the simplest and better out of all the options. ChrisM's version believe it or not is easier and simpler to maintain than the version I wrote.

BTW thanks ChrisM.