Those Raleigh double ended brake cables were phased out by about '64. It will be impossible to give it your bike an exact date because of Raleighs screwy serial numbers so pick a year...I'd call it a 59 Triumph and move on with the restoration. It's a decent Raleigh and things should clean up really well. I'd consider building up a 3 speed rear wheel for it too. Late 50's Sturmey hubs abound in Britain.

edit, Auchen, I think the second tier marques lost the BB oiler (and pump pegs) earlier than the standard Raleighs. I can't tell from the pics that this one is lacking for one.