The amount demanded looks correct, and will be made up from: -
1. PCN Penalty £160
2. Charge Certificate (50% addition) £80
3. TEC Registration Fee £10
4. Compliance Stage letter from bailiffs £75
The bailiff fee is a statutory amount.
If you don't pay up soon, they'll visit the address on the warrant to try and get the money, and charge you £235, which is, again, a statutory amount defined in the regulations.
It is probably best to make payment now to avoid the additional fee for a visit. Paying the bailiff has no effect on whether an Out-of-Time Statutory Declaration will succeed or fail. However, what is most likely is that you have failed to keep your V5C Registration Certificate up-to-date. We see this regularly on this forum, and it's very difficult to get the matter reverted to the PCN stage once bailiffs are instructed. Why ? Because you have to submit an Out-of-Time Statutory Declaration that you didn't receive the PCN, not one that is 'in-time'. Councils can object to OOT declarations and invariably do so, stating that all enforcement documents were sent to the name and address recorded in DVLA against the registration number of the vehicle.