Stolen crypto from wallet

I recently had 6,000 cardano stolen. Current value around 2 grand. I paid about 5 grand for it at the time. If I applied for negligible claim. Would it be at the value it was stolen or the value I paid for?

Forgot to say the value it was when bought sorry. How long does the tax credit last for if you succeed in applying?

Hi,
We can not give individual tax advice on this forum and you should use the webchat facility if you need advice on your specific case however you should consider
CRYPTO22450 - Cryptoassets for individuals: Capital Gains Tax: being defrauded
and 
CG13155 - Introduction and computation: occasions of charge: assets lost/destroyed/negligible value: involuntary transfers
Thank you.