Lyca mobile use EE's network (same as 1pmobile), however you need a chargeable activity like a text every 90 days. There's also Vodafone which has a chargeable activity requirement of 180 days.That's why I mentioned 'over the next 120 days' if I find it useful I'll put another £10 on.
No way I'd go on O2 again with GiffGaff, absolutely useless in my area.