Student looking for best nose isolation headphones for <£30 (please read fully)

[London123]

Hey first time poster.
 
So let me make myself clear.
 
I'm currently at university and have to go through 100s of lectures (it's that sort of subject) but I get easily distracted by even the quietest of noises when I'm reading (it's not that I find it annoying but I'm actually looking for distractions after a long day of lectures). I can't listen to music when I'm reading (maybe some quiet classical)  so I need something that will block off most noise while I'm reading even if I'm not listening to music. 
Additionally though, I need something that gives clarity of sound because I listen to lectures sometimes that sound quite muffled on my current Samsung earbuds so anything that increase the clarity would be important.
I'm not to fussed about how amazing music sounds, but I do listen to it on the London Underground occasionally (thinking about trying audiobooks too) so the noise cancelling ability would be awesome  as well as good quality sound. 
Ideally it would be something that's not too much of a hassle to carry around but is also durable.
And finally I can't wear earbuds, I've tried all types and they're just not complimentary to my ear hole so it will have to over the head.

I know this is A LOT to ask for under £30 (I'm stingy and not very well off student) but could you please tell me what headphones come CLOSEST to these specs, the cheaper  the better - but again obviously I want them to be durable and not be spending another £30 for new ones next month.

From my research I've seen the HD201s/202s (not sure out of the two either) which come sort of close but I am no expert and they have their flaws too, so would love any advice, would be greatly appreciated. 

Thanks!

L123

EDIT: NOISE ISOLATION is probably the wrong terminology - I'd be happy to hear advice from Noise Isolating OR Cancelling Headphones

 

[rubinstein]

I guess you would try sennheiser in ear phones something like cx 300, 400 or 500.

 

[London123]

Maybe I'm using the incorrect terminology cause I'm a bit of a noob at this stuff but I can't use in ear headphones cause they just fall out of my ears every few minutes, It's a problem I've had with all in ears, my ears just don't let them fit :|

 

[rubinstein]

the silicon buds come in three sizes (S, M and L). M fits perfectly in my ears. I can have about ~ 60% of noise isolation without music.

 

[London123]

I've tried all sizes of in ear headphones and find it annoying that they fall out, so I'd prefer any suggestions that use a headband, ear-hook one's are my second choice.