EoK , if part of this is to reduce time intervals on different SIDs why move MID and SAM tracks much closer together . I know I am an amateur but while the logic of the LHR argument holds up the practical implementation seems to negate what they claim they want to do.
If it helps, the declared objective of the trials is as follows:
"This SID Trial package introduces six westerly SIDs, with the intention of investigating reducing the angle of divergence between RNAV1 SID tracks for one minute departure intervals. Currently a one minute departure interval would require an angle between SID tracks of 45° or more, however it is hoped that data gathered by this trial may lead to a reduction of the angle to between 10° and 30°"