Raimey,
Thanks so far, hoping for more...
There are no other Sauer type markings visible, no old British marks, no doll's head or Greener crossbolt, no Double Grip Gewehr marking....
There are two sets of initials on one tube: WD and AL (? faint).
Additional London marks are 18.3, 18.4, crown/R, LP/96 (London Proof 1996-?).
With kind regards,
Jani