I know I'm replying to an old-ish thread here....
I am using EE for my broadband, since I'm stuck with 8Mb with BT. With EE I have two SIM cards, each with 50GB month allowance. It's not cheap - £30 for each SIM - but 50GB per sim is reasonable.
I am not sure if these still offer these packages routinely, they just seem to be occasional offers.
My line (not necessarily the line referred to in this post, if any):
Zen 8000 Pro (832 / 8128)
Cisco 877 Router
Eclipse > Ace > ADSL24 (Enta) > ADSL24 (Murphx) > AAISP > Zen