You probably have a 5.4.7 client disguised as a 5.4.8
Get the right client here: http://devil.tauri.hu/~kimbatt/english.html
So that link is client from WoWCircle which is perfectly fine (mostly), however their wow.exe is hex editing to display 5.4.8 (18414) instead of 5.4.7 (18019). You only need to update your wow.exe from Tauri minimal client and change the Config.WTF realmlist.
You can actually tell if your client is 5.4.7 by the size on windows.
5.4.7 = 12.844 KB
5.4.8 = 12.847 KB
So this repack is 5.4.8 = 12.847 KB
:good:
Thank you both Jack and Lingx,
I downloaded the Tauri minimal client and swapped the WoW.exe over as per instructions from Jack and I am pleased to say that I can no fully log into the realm and my client is now fully 5.4.8 (18414) and I can play. Thank you for your amazing repack and I look forward to future update, Many thanks and the help was greatly appreciated