bomar97,
Reading the sections on the Trials Mk V's in Skennerton's books is, admittedly, a bit confusing as to the dates and number of Mk III's so converted, but, if you take a magnifying glass to his photo comparing a Trials rifle to one from the production run, you will see the Trials rifle was made from a 1915 Mk III.
If you zoom in on the Trials rifle I referred you to at the end of the MKLarticle, you will see that rifle was also converted from a 1915 Enfield Mk III. (I really should retake those photos.) Examination of both sets of photos reveals more dings in the fore-end, as well as a missing rear aperture for the long-range dial sight on the rifle in Skennerton's photos, thus proving they are, indeed, different rifles.
At this point in time, these photos are of the only two examples of the Trials rifles known to exist, (don't even know if the Skennerton rifle still exists, as the photos were originally just credited, "Old Photographs..."), as even the old Pattern Room Collection doesn't have a specimen, but, the photos do tend to bolster my personal feeling that the Mk III rifles converted into Mk V Trials rifles were probably taken from those in production at the time, that is, in 1915 apparently.
Does anyone out there have another example we can use for corrobaration?
Terry