Nice Davyp, cracker. Dark head, very dark pectoral and dark rigid tail which doesnt look like it would collapse in the hand when tailed. Nice dark dorsal fin too. No question that the fish Eoghan put up has salmon like colouration on the body and fine spotting but as you say that isnt unheard of on trout(the last trout in those pics of mine is one of them), other characteristics point to trout. Its tail wouldnt be tailable as Viper has already pointed out. Look how far infront the front point of the anal fin is to the rear point on your salmon. On a trout when the fin is held down closed ther front point reaches behind the rear point. As with other features this one too is often hard to guage in a photo and is more reliable to refer to when you have the fish in front of you.
2013 Sea Species:- Bass, Flounder, 5 Beard Rockling, Shore Rockling, Whiting, red gurnard, grey gurnard, Pollack, coley, mackerel, sea trout, cant remember cos I didn't update at the time.....
2012 Sea species:- Pollack, Coley, Mackerel, Cod, Bass, Sea Trout, Haddock, Plaice, Dab, Flounder, Red Gurnard, Grey Gurnard, Pouting, Whiting, Corkwing Wrasse, Ballan Wrasse, Lesser Spotted Dogfish, Brown Trout caught on beach.
2011 Sea species:- codling, L.S. dogfish, coley, whiting, pollack(4lb 3oz), sea trout, shore conger eel (15lb), ballan wrasse, grey gurnard, plaice, dab (and lobster).
For what it is worth, I am on the side of this fish being a Salmon. The tail is a dead give away, any Sea Trout that size would most definitely have a convex tail, the lack of spots below the later line is also nothing good indicator that this is a Salmon. The Maxillary on a Trout comes behind the eye and on the Salmon it ends at the rear of the eye. For a definitive look at the two fish see here http://www.letsflyfish.com/fish.htm I would just add that if you close the anal fin up to the body, the outer ray of the fish, in a Trout, is longer that the inner ray, that of a salmon is equal or even the inner ray is longer.