If you are talking about the song that comes on quite a lot in Season 5, then it's Embers by Just Jack. Credits go to the wonderful people at Channel 4 Viewer Enquiries.
The Veronicas - Untouched
The instruments thats was played was the piano,gutair and drums
The Bittersweet Symphony by the Verve?
It Doesn't Matter Anymore features several violins.
drinking beer and partying
There is no such thing as a certain "part" of the violin that produces a melody. The melody of a song can be played by any instrument- the violin, the viola, the cello, the double bass, the winds, or even the occasional percussion. The Melody of a song is the main part of a song. Usually, if referring to JUST THE VIOLINS, the 1st Violins normally play the melody, and the 2nd Violins usually play the Harmony.
Just type in 300 violins on iTunes and it will come up
Violins and Piano
The Veronicas - Untouched
Note that the concert keyy will be different and that the translating into the correct key will be difficult, it will work.
"Peace of mind" - can fall asleep listening to it
Unfortunately, without more specific information or a link to the advertisement, it is difficult to identify the exact song being played in the Katie and Peter Stateside current ITV2 advert. However, if it starts with "A Whole New World" and then transitions into something with violins, it could potentially be a remix or rendition of the original song or a completely different track.
The instruments thats was played was the piano,gutair and drums
Mainly violins, violas, and cellos. So an orchestra.
The Bittersweet Symphony by the Verve?
It Doesn't Matter Anymore features several violins.
drinking beer and partying