This sounds like a very unfortunate situation.
Your son has been charged with 2 x criminal damage to 2 x chairs. You think he has admitted throwing clothes out but not to damaging the chairs. I am assuming that the chairs belong to you and are located in your house which you son either lives in or was visiting. If this assumption is wrong let me know.
You have signed a statement in a notebook this is very likely a statement with the full declarations as to truth etc. written on it. I am assuming your statement sets out the damage to the chairs.
Now that your son has been charged and there is a court case pending you are a witness and do not control the case. It is the CPS who will be bringing the prosecution and who will decide whether the case should be brought. They have 2 tests to satisfy if they want to continue with a prosecution. Firstly they must be satisfied that there is sufficient evidence that it is likely they will be able to secure a conviction if the case goes to trial. Secondly, they must be satisfied that it is in the public interest to prosecute.
It sounds as though they likely have sufficient evidence.
You are under no legal obligation to attend court unless you are ordered to attend court. This is done by the CPS applying for a witness summons. This case will be heard in the magistrates court and, at least in the Metropolitan area, witness summonses are rarely issued in the magistrates court. If the case is listed for trial and you do no attend then the CPS will need to apply for an adjournment and they may well have difficulty obtaining one. If an adjournment is not granted and you are a witness who they need and you are not there then the case will collapse.
So you could simply wait and do nothing and not attend court and hope the case collapses. There are a number of drawbacks to this. One you will waste court time and if an adjournment is granted you will be summonsed to court.
I would suggest the following. Write to the CPS/Police explaining that you do not want the case to proceed. If you di d not know that the notes you signed would be used against your son say so and point out you feel you have been misled by the police. Explain why you do not want the case to proceed and state that you will not attend court. Make sure that you do not put anything in the letter that might indicate that anything in your statement might be untrue as thi could land you in trouble.
You should send a copy of the letter to your son’s lawyer as well. He will not want to talk to you and if you send it with a letter to him simply state that you are sending it to them so that their file is complete.
Hopefully your son’s lawyer will make representations that it is not in the public interest to proceed which may be successful.
If you send a letter like this it will probably lead to the case collapsing. However, the CPS Is not very efficient and will probably do nothing in response. It is possible although in my experience very unlikely that the CPS will respond by issuing a witness summons.
You would be able to challenge a decision to issue a witness summons or to proceed with the prosecution against your wishes by way of a Judicial Review but this is a very expensive sort of action to bring.
In short your choices are to do nothing and not attend court for the trial or, the better option of sending the letters suggested above.
I hope this answer helps but if you have any further questions then please let me know.