Default [Q] Strange data problem, Nexus 5

Hey all,
Recently, in the last 2 weeks, I've been having an odd data problem on my nexus 5 (4.4.2)

Where my data icon is orange, instead of white, yet I have full working internet access.
However, things like WhatsApp, Facebook messenger, won't sync until I get WiFi, but yet, I can send and receive messages?
I've tried rebooting, the airplane mode trick, full factory reset, and new APN settings.
I'm on T-Mobile/EE UK. PAYG. Been with them a week-ish.
I was on orange/ee before, and that stopped working entirely, but that was orange, not my phone, cos apparently my number didn't exist. Lol
I deleted all my apns and put them all back again, which fixed it for about 5 seconds, now its back orange again!
WiFi works perfectly.
I get an error when trying to sync Google sound search. But everything else works fine.

Any idea what it could be?
APNs? Phone, or network?