My name is ***** ***** I am a NSW Solicitor. Thank you for your question, and will do my best to assist you with your question. Please understand this is not legal advise Please understand this is not legal advise but a guide to assist you.
It is legal and you cannot force him to pay for the fence.
Because you signed the contract for the land with that clause in it you have agreed to be fully responsible fro the fence and not charge him.
Having said that, you can approach them and ask if they can make an exemption. If they agree then this amends the contract and you can then get something towards the fence. But it is legal and you cannot force them to pay.
I hope this makes sense and is of assistance, even if it is not what you wanted to hear. If there is nothing further
thank you for using my services.
If I have missed anything, or you have any further questions please let me know
If there is anything else in the future please do not hesitate to ask.
Please do not forget to leave positive feedback.