Does it have to be EE? A lot of people prefer GiffGaff, for cheaper rates, and that's who I normally tell visiting friends from overseas to go with.

You might even find someone who'd post you some sims for free, as giffgaff users get a referral bonus!

(I use EE, because I'm on a short-lived but amazing price plan, but their billing and customer services are both pretty bad so I wouldn't recommend them otherwise)