The correct translation should be
"Voi ei, Viikingit haluavat käydä Lontoossa."
Often we just say 'o-ou' as well. "Voi ei" is literally "oh no", but yeah, it carries a similar meaning to 'uh-oh' (just stronger; more negative).
Anyway, either something should be in both languages or neither.
uh-oh can be translated as "voi ei"
Is one "voi" insufficient here?