Further to my last post, whils searching for DtsRunDec (the decoder app), I found this thread on sqlforums.com. One chap (jamespua, near bottom of page) says that if you use the DTSRun utility but add the switches /!X /!C at the end, the utility will decode the name for you (without executing the package) and put the decrypted run string into the cliboard which you can then paste out at will. Having tried it, it works perfectly.
DTSRun /~Z0xDECE772DF6021A7ED260B31A2A37454F9614F6426C26B75B35481216F12946BB2ED19DC1E116ECD0C39E279544DAEE48E088FCE1CD35D0A1A99E11530ED82E9E97FF95CD4ECB7AD5D56F66CA8CC060E3E08B99BF3478B3DF4ADFD1912C097B77C9C2C44419F78FC5C7B6E8A269A9840E5387B48AB10106F2AECEDBE59C1DB35A7811F81D04ABF01F5E67C148778028B165D51BDF88DEE3CBF8F7582B6CA554D826B9BB /!X /!C
DTSRun /S "<server>\<instance>" /U "<uid>" /P "<pwd>" /N "<package name>" /!X /!C
Obviously, names have been changed to protect the innocent!! Top marks to jamespua on sqlforums for such a handy tip. The full documentation for DTSRun and it's switches is here.