Here is where you can download the 7.0.23 pack (and older packs too): https://code.google.com/p/download-client/downloads/list
Here is the 7.0.15 download http://www.atomicgamer.com/files/93016/ultima-online-classic-client-v7-0-15-1 or alternatively ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaUkpiN2t5R0dIZTQ&export=download
7.0.20 ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaTnZEMmhjZW5oYnc&export=download
7.0.24 ... http://web.cdn.eamythic.com/us/uo/installers/20120309/UOClassicSetup_7_0_24_0.exe
7.0.30 ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaeEJHNXA2MTBaMk0&export=download
7.0.34.22 ... http://files.theabyss.ru/uokr/2D.rar
Here is the 7.0.15 download http://www.atomicgamer.com/files/93016/ultima-online-classic-client-v7-0-15-1 or alternatively ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaUkpiN2t5R0dIZTQ&export=download
7.0.20 ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaTnZEMmhjZW5oYnc&export=download
7.0.24 ... http://web.cdn.eamythic.com/us/uo/installers/20120309/UOClassicSetup_7_0_24_0.exe
7.0.30 ... https://docs.google.com/uc?id=0B5JIbJ4zjyOaeEJHNXA2MTBaMk0&export=download
7.0.34.22 ... http://files.theabyss.ru/uokr/2D.rar