this isn't really about Parcelforce, and their success rate with delivering parcels in general.
It is a single driver that has caused damage to your property. Both the driver and Parcelforce would be liable for this damage, but you would typically claim from the one with the deepest pockets- the company. That is your legal right. It is a civil matter. Technically, criminal damage has also occurred here, but the police will not be interested given the value.
The downsides. The burden of proof is on you. You need to consider your time, and how much you value it. To claim a legal right, you may need to go to court. Sometimes, your power is in the threat of taking it further.
In the first instance, you need to write to them and make a claim for the damage. Quantify the cost of a replacement cat flat, etc. Be reasonable- if a spare part is available, it would be unreasonable to claim for a whole new one. If you need a new one, it must be comparable- you can't profit from the incident. Take pictures, and show as much evidence as you can.
When you make a claim, whether they do anything about it, or ignore you is a different matter. To be honest, there are many (most) companies that will ignore claims from the general public for small sums of money, because they know that you will not pursue it. A letter from a solicitor tends to help here, because they take it more seriously, but you have to pay for that. If they ignore you after a couple of letters that is when you may have to go to court. This is a small claims court matter, which is designed for the layman to use, but it is still hassle. As I said before, you will need to prove that the driver caused the damage and if you have not already convinced the company that you have a case, you are probably not going to have any new evidence now.
I would suggest that you find the email address of the CEO and write an email. Be polite and explain what has happened and the cost of rectifying it.
https://www.ceoemail.com/s.php?id=ceo-9552 no idea if this is current.
NB this is not legal advice. it is a quick note from a woodworker given the limited info in your opening post.