Hi Oz lady,
I had a sort of similar thing happen to me over the past day or so, but not involving porn.
I decided to get me one of them thar custom avatars from gravatar, as directed from A2k.
Immediately after the avatar was up and running, I experienced a paypal popup banner when browsing through A2k.....and ONLY A2K.
I asked here but to no avail, and ended up clearing virtually everything off my tablet (samsung ---- android thingy).
It was THEN that I hunted down a free antivirus on google play, which seemed to have a lot of 5☆ ratings.
I downloaded the app and scanned....and got rid of so much crap you wouldn't believe!
You have ipad which is obviously apple and different, but I would have a go at getting in to their app store and browsing their antivirus/malware stuff.
It may be free, it may not...but now I know there's apps like that out there, I'd wished I downloaded it yonks ago.
PS.....the clearing of crap didn't cure the popup thing with me, it took a long methodical backtrack hunt to find it.
The popup only happened when on A2K, and the only thing linked to A2k was my email address which I had to link via gravatar in order to get my avvie working.
I tried severing links with gravatar but found that it was impossible to close the account.
The only way I could do it was by closing MY email account and setting up a new one.
To say that I found this annoying would be a slight understatement.
Immediately, the constant, annoying popup problem disappeared.
Maybe gravatar doesn't do this to ordinary PC users, maybe it only happens via android or chrome?
All I know is that I will steer well clear of it in future, and if anyone knows another way of putting up an avatar I'd be grateful.
Not that I'm that bothered......
Anyway, hope you find an app to suit.