If you sell within 5 years you will have to repay some or all of the discount:
Example:
If when you bought under Right to Acquire, the house was valued at £150,000, and you were allowed a discount of £15,000, the discount you were allowed was 10% of the value.
If three years later you decide to sell your home, and you get an offer of £200,000 the ‘discount’ element for repayment is: £200,000 x 10% = £20,000.
As you are selling in the third year 60% of the ‘discount’ element is repayable: £20,000 x 60% = £12,000.
There are some exceptions to repaying discount, e.g. for sales to an existing joint owner, spouse, former spouse or a member of the family living in the property.