The time limit to claim an SDLT (Stamp Duty Land Tax) refund in the UK depends on the specific situation that makes you eligible for the refund. Here are the time limits for some common refund scenarios:

1. Overpayment: If you have made an error on your SDLT return and overpaid, you must claim the refund within 12 months of the filing date of the original return.
2. Multiple Dwellings Relief (MDR): If you are claiming a refund due to MDR, you must make the claim within 12 months from the filing date of the SDLT return.
3. Replacement of the main residence: If you have paid the higher rates of SDLT for additional properties (3% surcharge) when buying a new main residence before selling your previous one, you may be eligible for a refund of the higher rates if you sell your previous main residence within three years of purchasing the new one. You should claim the refund within 12 months of the sale of your previous main residence or within 12 months of the filing date of the SDLT return for the new residence, whichever is later.

To claim a refund, you should contact HM Revenue and Customs (HMRC) and provide the necessary information, including the details of the transaction, the amount of SDLT paid, and the reason for the refund claim.