A recent discussion regarding the use of the term Oriental, prompts me to ask if the word Limey is regarded by the English as derogatory. If not, are there any derogatory terms for the English, Yanks, Aussies, or Canucks? Surely the Germans or the Japanese or even the Argentinians might have some choice names.
Of course ‘Limey’ is not derogatory.
Anyone should know that an insult aimed at a Brit merely shows the inferiority of the insulter. 
“The Racial Slur Database” will satisfy nearly all your racist verbiage requirements.
http://www.phix.com/~ryan/rsdb/
Try these:
Crumpet Stuffer, Feb, Jikky, Lobsterback, Pom, Redcoat, Rosbif, Sassenach, Teabag, Tommy.