You'll have an duplicate config file somewhere that also contains entries for the premiership - remove it and the kits should show. (If you have the conference creased kits installed, I think it includes lines for non-conference teams in the config file - open the config file in notepad and remove the lines for non-conference teams).
Also turn off the skin cache in the preferences screen and switch to a different skin. (Once the kits appear fine you can turn the cache back on and switch skins back).
My kits appear sometimes and not others 
Linear Mode
