Sheesh, that doesn't sound very good at all.
I've been having a rather frustrating day, it seems like there's not a single network out there that offers a solid deal. Orange are saying it's a 500mb limit and that's that, I can't pin them down to unlimited. Some CSR's say if I go to 501mb I'll be charged, some say I'll be emailed. Sod that.
I call o2 about their simplicity sim-only deal with web bolt on. First guy tells me that the 250mb cap has been scrapped and there's merely a don't take the piss fair usage policy (I'm paraphrasing of course). Second salesperson says it's actually about 200mb. I then talk to a CSR and she says it's completely unlimited but I'll be charged for downloading/video streaming like youtube. No good.
T-Mobile I've not even discussed what sort of things I can use, they have a 3gb FUP but everyone on T-Mob over at xda-developers say that the download speeds on HSDPA is atrocious.
I've not even considered Voda as there doesn't seem to be a way to add a data plan to their sim only deals on the website.
Guh.