Advice on attempting to claim rent arrears from a final year foreign student

Rent Arrears

Happy New Year

We have a student who moved out still owing us about £600 rent (that's after deducting the deposit).
We understand that we can claim rent arrears up till 6 years afterwards BUT this student is a foreign (EU) national and is probably going to leave the country this May. And because she's in her final year she will probably never come back. So the question is more like - is it worth attempting to claim the money back? We don't want to spend money on the claim if it's unlikely that we will get anything back.
Also, is it possible to say how long the process may take given that the student is unlikely to cooperate (she and her guarantor have broken off communication with us). And even if we eventually get an award against her, she'll probably ignore it and leave the country - does a UK CCJ have any affect on an EU citizen?
We were thinking of contacting other people in an attempt to recover the arrears and need to check whether giving out information about the Student is allowed under GDPR rules - our Privacy Policy, to which the Student agreed, includes a statement "... information may be disclosed to any relevant party assisting in the recovery of this debt... "
Besides wanting what she owes us, we'd like to reduce the chance of her doing it again, to say her current landlord. Is there anything we can do about that?
thanks very much