Nice shooting Lou! You know the order that these were made - what do you make of the diagonal pattern? (am thinking "wheel of pain" type feedback). It would be interesting if you included the shooting position, timing of shots (rapid / slow etc) and any load info with weather conditions..
Here are some of the links (from searches) mentioned earlier...there may be more..
How to sling the No4 Mk1(T)
Using the British canvas sling for shooting purposes.