Prop head.
I have the paper version of the Scheme Development report all 380 pages. Section 3 is 25 pages containing details of Runway component. Variations of options ( so they cannot make up their mind) of 2295,2800,3200, and 3500 on page 39 their best summary lengths are between 2295 and and 3500.
Existing runways are 3902 and 3660, but both are used with displaced thresholds reducing these lengths.
Both R3 and the northern runway will have exits on one side only, as opposed the current southern runway for T4.