No it isn't. When you deploy it as a noun, referring to the specific country, it needs the definite article. Some nouns, you can do without - but this noun, you can't.
If there exists a rule that allows an omission of "the" for "UK" in certain context, will you send me $20k on top?
If you aren't able to prove that in this context I speak formally rather than informally, and in the latter "the" may sometimes be omitted, will you send me $30k on top?