I'd be very surprised if it isn't just intended as a "townie" clause, to protect the vendor from complaints (and possibly obstruction) about noise, smells, mud on road, etc. But I too would not be comfortable with that wording.
Conveyancers can be pretty lazy, and solicitors often use junior staff for run-of-the-mill stuff and don't always check their work... So good for you

, reading it through yourself as well, and spotting this. If the solicitor you're using is not used to agricultural holdings, I suggest you find one which is, and even better if in the area you are moving to, as there could be local practises it would be helpful to be aware of.
If it were me, I think I would have tried having a conversation with the seller to understand their need, explained my concerns about the wording as it stands, and then hopefully jointly got the two sets of solicitors to work on finding wording that meets the needs of both parties.
Often in a purchase, the seller has no interest in preserving a good relationship with the buyer, as they will probably never meet again. But in this case, you will become neighbours, so one would hope and expect that the seller would be willing to help resolve this or any other matter through conversation initially, so that solicitors can then be instructed to scribe something that meets everyone's needs.