Also, it's only about £2k to sort
Then sort it yourself. I do not think you will have success convincing a seller to pay for this.
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Sure, but that doesn't really mean anything in this context. They can choose to sell to someone else who doesn't care about this issue.
Doesn't look like it's a legal obligation so they can just tell you no if they want.
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Then sort it yourself. I do not think you will have success convincing a seller to pay for this.