An Open Contract

I would like to quote from a well-known law book about the definition of open contract:

If a contract for sale specifies merely the names of the parties,a
description of the property and a statement of the price,it is
called an open contract.When this form of contract is made,the parties
are bound by certain obligations implied by the law.
This quote comes from Dr.Geoffrey Cheshire in the 10th edition of The Modern Law of Contract.
At hand is a case where the following note(handwritten) had been signed by three parties being the intended seller,buyer and a witness.
IN consideration of the sum of Rm22,000.00 only being 10% of the selling
price for the piece of xxxxxxxxxxxx The total selling price for the
whole piece is Rm220,000.00 only.Balance amount Rm198,000.00 only.
I namely xxxxxxxxxxxxxxxxx,i/c xxxxxxxx ressiding at xxxxxxx do hereby
give my Irrevocable Consent To Sell the abovementioned property to
Mr.xxxxx i/c.xxxxxxxxxx .

The duration for the completion of the sale is Three(3) plus 1 month@
10% interest per annum. The signing of the Sales and Purchase Agreement
is to be signed upon the Official Searched(sic) at the Land Office.

Dated this x day in the month of xxx,xxxx.

Sgd. sgd. sgd.
x x x x x x x x x
(Vendor) (Purchaser) (Witness)
As a practising lawyer I would think that this is no child's play. Remember,10% of
the sale price had been paid.No right thinking person would dish out such a big sum if he was not serious about the whole deal.To me this note had done what it had to do ie :to express the simplest desire of the Parties ,it was that the deal was on.

After the note was signed things did not proceed as it originally intended, one of the parties changed its mind.The seller did not want to sell.Even after a few letters from the buyer's solicitors.
At first the seller rejected the draft agreement because there was a power of attorney clause. Subsequently the power of attorney clause was removed, the seller still refused to sign the agreement.

The buyer brought the matter to Court.Seller put up a few defences,the High Court judge after hearing the arguments of both sides ruled that the buyer had no right to force the seller to sell.Among the reasons given were there was uncertainty as to the terms of the agreement, that the buyer took unfair advantage of the seller.However when this matter went up for appeal.The jugde's reasoning was not accepted by the appeal court judges.The judge's judgement was examined thoroughly
by the appeal court.The appeal court found there was no justification for the judge to refuse specific performance to buyer,in other word the seller was ordered by the appeal court to proceed with the sale.The seller also had to pay whatever damages that the buyer had sufferred for the delay.