For anybody who pre-ordered via Carphone Warehouse and picking up from store. Got two emails this morning saying that my order was dispatched (phone and Gear VR). Went to the store after work and they told me they will basically be getting the phones in over the weekend, Monday and Tuesday. Mine hasn't arrived yet. Even if my phone arrived early they won't tell me until Tuesday 8th of March.
I suspect my GearVR will be on the same day or not long after.
If you're friendly with your CPW shop person, I recommend checking in on the Monday to see if they might sneak it to you a day early. I'm definitely going to try that.