There is no separate "cybercrime" legal aid scheme. Offences such as those under the Computer Misuse Act 1990 (unauthorised access / hacking), online fraud, malware, denial-of-service, and cyber-enabled offences are prosecuted as criminal matters — so they're covered by criminal legal aid, delivered by criminal defence solicitors.

• Legal aid for criminal cases is means- and (for some) merits-tested.
• At the police station, advice is free to everyone, regardless of means.
• Look for a firm that does Criminal Defence and offers legal aid (listed below).
• Complex cyber cases may also touch fraud, data protection or IP — ask the firm about relevant experience.

General information, not legal advice. Eligibility is decided by the Legal Aid Agency. Check GOV.UK — Legal Aid.