Yes, I should have used {} all the way: 
s{(\Qhttp://v2vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+IDENT=\E)US}{${1}UK}g

[download]
Note that both the pattern and the replacement have their own set of parens. You may write: 
s{(\Qhttp://v2vi.click4assistance.co.uk/c4a.aspx?AccNo=Inter12109&
+IDENT=\E)US}
 {${1}UK}g

[download]
as well.

In reply to Re^3: regex issue by JavaFan
in thread regex issue by rahulgsp83

Title:
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