Government departments are almost always uniformly 30 day settlements, very few exceptions.
Lenders are generally open to 60 day settlements, but you'll have trouble getting any more than that. They don't care too much about the deposit amount, their primary interest is clearing the entire debt as quickly as possible.
You might get an extended settlement if you offer a really good price, but even then it's unlikely because they don't want to hang onto something too long when there's a risk of not settling. If the sale falls over they want to be in a position for a quick turn around.