Thank you very much for updating us.
You may wish to look into pursuing a civil claim in the County Court against Northern for what they have done. They had no right to prosecute you, and they arguably breached the GDPR by misusing your personal data to pursue their unlawful prosecution.
Breaches of the GDPR entitle you to claim not only for direct losses, but also non-material damages such as distress and inconvenience. Clearly the prospect of this prosecution has caused you a lot of stress - that is certainly something which would give rise to a non-material damages claim if a GDPR breach is established. Such claims typically range from £250 (i.e. it's not going to be a minimal sum) to several thousand in more severe cases.
The other, more nuclear, option would be to pursue a civil claim for malicious prosecution. There are several elements you need to prove for a malicious prosecution claim, which may not all be met in your case. Nevertheless it would be a way of holding them to account for their misconduct.
Please do let us know if either option is something you are interested in, and we can provide you with more information on what you can do and how you could go about pursuing it.