screen bleed? on my nokia 5200

doolally_2

Hi, I've had my nokia 5200 for just 7 months and yesterday i noticed a black mark right in the middle of the screen, it looks like a lot of dots in a wavy row. It's quite annoying and it's there when i take photo's. Last night i rang tesco as thats were i bought the phone, and they said it could be a screen bleed, i'd never heard of this but she said that it's caused by pressure on the screen of the phone. To my knowledge i haven't sat on it or anything so she said she'd send me a jiffy bag to send it to the repair centre. They said they will repair it free of charge if it is a manufacturing fault but if it's accidental they will charge me although i don't have to have the repair done if i don't want to. Has this happened to anyone else? I'm guessing it WILL be accidental and how much am i looking at to get fixed? i've lost count of the number of mobiles i've had in the past and never known anything like this. The other werid thing is this morning the black dots have turned purple!!!!!