It all depends if the lead is inside or outside 4DME.
And yes, for LHR certainly all these procedures were in the MATS Part 2.
The new version of TBS has complicated things slightly.
Before TBS, it was pretty simple. If the lead was outside 4DME and wake turbulence spacing was infringed, Director had to rectify. If the lead was inside 4DME, then tower gave a caution to follower when that infringement reached 0.5nm.
Don't forget though, this was with procedures that only provided wake turbulence separation to 4DME, not to touchdown.