CII J02: Stamp Duty 18+3 Relief Calculation

Good morning or evening everyone. I have recently decided to pivot from a long career in the IT sector into the financial services industry and I am currently dedicating a significant amount of time to preparing for the CII J02 examination. I find the subject matter regarding residential property transactions and Stamp Duty regulations to be fascinating, yet I admit I am a bit rusty with financial calculations compared to the coding work I used to do. I always try to approach these exams with integrity and want to ensure I understand the finer points of the syllabus rather than just memorizing the answers. Thank you in advance for taking the time to read my post. I have a question regarding the calculation of Stamp Duty and relief entitlement under the main residence rules. Specifically, I am focusing my revision on the scenario where relief is available for the 18+3 years ownership structure as it appears frequently in the study material. I am unsure if the relief applies to the entire purchase price of the property or if there is a capped value limit to consider when the exemption is triggered for senior citizens. Could someone please help me clarify how the tax calculation changes when the 18+3 rule is successfully applied versus standard stamp duty rates. I would be extremely grateful for any guidance.