Great Britain Pound(GBP) is 英镑
Great Britain Pound is Translated into "英镑" in Chinese Word by China Official and Banks.
"镑" is "Pound" in Transliteration.
Reference by Bank of China: http://www.boc.cn/sourcedb/whpj/

Chinese People Call it "英镑".

Great Britain is Translated into "英国" by China Official.