I hope I can assist.
As a tenant you are responsible for the furniture the landlord puts into the property. Therefore the landlord can claim the cost of replacement from you. You did take a risk in removing the armchairs from the property.
The landlord is entitled to claim the cost of the armchairs.
My only suggestion is to negotiate, if you can, to reduce the amount you have to pay.
Does the landlord hold a deposit? If you do not pay the landlord can deduct the amount from the deposit.
Unfortunately I do not think you are in a strong position to avoid liability.
Do try to negotiate.
Yes, do try to establish the cost of the chairs. Hopefully you can establish this with the landlord. If the landlord does not produce receipts or establish the value of the chairs and you do not pay then the landlord will seek to deduct this from your tenancy deposit of £3500.
However, our tenancy deposit should be registered with a deposit scheme. This is a legal requirement. If you do not pay and the landlord wishes to deduct this from your deposit at the end of the tenancy then the deduction and reason behind it has to be disclosed. You can then dispute this via the deposit scheme. The scheme will suggest some form of alternative dispute resolution to resolve the dispute but you and the landlord both have to agree to it.
No problem. Glad I could help. If you need any further help please just send me a message. I am happy to assist further.
I hope you resolve the issue. Best wishes...