Annoying banner ads

[JimmyJam]

I looked at a website for narrow boat holidays a couple of weeks ago. Since then the same bloody banner advert for this company is repeatedly showing at the top of my page when looking at PH. It's really pissing me off and to make it worse my OCD is going mad because it doesn't even fit the page and covers half the PH logo. I understand this happens and I dont mind for a couple of days or even a week but this has to be more than 2 weeks now stuck with the same banner aaarrrgghh. Anything I can do!?

[Switch]

Clearing your cookies should sort out that ad following you around.