Sadly, the best options are online. For my Ipaq, I bought an alluminium case with rubber shielding against being dropped from Ebay, for �10. PC World do sell them (if you can find any stock) but they are so tacky it's unbelievable - a leather one was �20, and only held the Ipaq in place with a stuck on piece of velcro; totally USELESS for my use, as I've got the tomtom navigator car kit and the velcro pad would get in the way.
Just because it's online, however, doesn't necessarily mean you have to pay online. Look for Ipaq cases on Ebay, and when you find ones you like look for the option to pay by cheque or postal order. Buying and selling by Ebay IS in law a legally binding agreement, and if you can pay by cheque or postal order you don't have to give anyone any card details. You'll get a good quality case at a reasonable price.