Obscure the password.
As it says, you have to file a defence or Acknowledgement of Service by 18 May.
If the latter, you have until 1 June to file a defence.
Your defence is that you, as the registered keeper, can not be liable because G24 issued the original PCN too late to transfer liability to you from the unknown driver, under the provisions of PoFA 2012.
Obviously you need to elaborate on that a bit, by quoting the appropriate legislation and the key dates which demonstrate lack of compliance.
Don’t forget that G24 said
The notice to keeper has been issued within the relevant time frames outside of the Protection of Freedoms Act.
Search the forum for many, many documented similar cases, and you will see that DCB Legal
usually discontinue defended cases, but you have to keep up with the paperwork until they do, including filing a defence.