Hi Nomadave,
If signing a binding financial agreement is your condition for allowing the sale to go ahead, you are within your right to refuse signing until they sign a binding financial agreement. How far along are the two of you in reaching a resolution? Is it a binding financial agreement for just this property, or other assets as well? Has the agreement been drafted? If not, you may looking into getting a lawyer to draft one up. Otherwise, your ex's lawyer will be doing the drafting and this may be not favourable to you.
From what I read, your ex's lawyer has not been breaching any professional ethics by sending you a sale. Unless the lawyer is reassuring you that this is just a valuation and not a sale, and stating it is alright to sign this valuation without consequences, and the paper they sent you really is a sale agreement. Your ex's lawyer is not your lawyer. They are not bound to consider your interests, just that of her clients. There are limits all lawyers are bound by, but it does not appear the lawyer has breached these limits. You are within your right to refuse. However, you cannot expect your ex's lawyer to look after your interests as well. It may be best to consider approaching a lawyer to represent you if you are having difficulty handling your ex and her lawyer.