+1.
The offer is in their NOR, I suggest you read this.
You can pay the discount of £65. You have 14 days from the date of this letter being served to do this.
Date of letter Friday 5 July. Therefore date of service is Tuesday 9 July, 14 days from which is 23 July.
They cannot renege/resile/backtrack on this offer, it's against the law.
The question is how could this be exploited.
Others will comment.