Over ear headphones for under £30

I'm looking for a pair of over ear headphones for under £30 max. Comfort is the key hear as they will be used for transposing songs. If isolate as well then great. Many thanks

Nobody can tell you what is going to be comfortable, or what will sound good to you.
These:
http://www.amazon.com/gp/product/B00012F7G4/ref=oh_details_o01_s00_i00 are an inexpensive pair of headphones that are over the ear closed and sound OK.
Over ear isolation headphones often sound muddy compared to non-isolating, but if you want serious isolation, at that price, you'll have to buy used or possibly build your own. The pair in the picture is my Frankenphone combination of the ones I just linked to and these:
http://www.amazon.com/3M-Peltor-H10...id=1355545373&sr=8-1&keywords=peltor+earmuffs

My son's ears are so sensitive we keep Etymotic earplugs or shooting earmuffs in the glove-compartment of the cars so they're available anytime we decide to see a movie. Wearing those earmuffs I made him he can hear and play along to music set at a low volume, or simply to the metronome, and it isn't uncomfortable even with his super hearing.
Seems like any headphones would work for transposing songs, but I wouldn't use the ones I made my son for mixing, because the bass is accentuated now.

If you are picky about sound quality, my advice is to go to a music store and try a few pair out for yourself. Sorry I can't help more.
Todd

Thank you very much for all that info- really good! I will bear all that in mind and could make my own i guess! Josh

If you can find someplace to try on those audio Technica headphones, I would recommend them. They were extremely comfortable for both me and my son. Made me regret cannibalizing them for parts, but for 29db of hearing protection ...