From comment on the FB thread, Tyron noticed a bright light (like a star) at 2.30PM, then did not see anything again until 4:15 when it seems like they first saw the object in the photos (which I'm 99.999% sure is a plane leaving a contrail) shortly after 4:30 he took 13 pics in three minutes, of which the above are the last two.
Just to add a bit more detail, this is what Tyron Osborne posted:
He was in Brixington, which is marked by the red pin here:
So Dawlish is roughly southwest, and he saw something in that direction at 2.30pm. It's not at all clear that the object he saw at 4.15pm is the same one, but he watched it and it was moving from southwest towards the southeast (Budleigh Salterton), ie moving roughly west to east but staying south of his location.
This is a sky chart for 2:30pm on December 28 from Exmouth:
The sun was towards the southwest, i.e. in the direction of Dawlish. (Note that the sky map has east and west reversed, because it represents the view as if it was held above your head.) It would be interesting to know where he saw the bright star-like object in relation to the sun. I can't think of any astronomical object that would have been visible at that time (Venus can sometimes be seen during the day, but unlikely that early in the afternoon, and it was to the east of south anyway). Could it have been the sun reflecting off another, unrelated aircraft?