You have a long wait, I Pre-ordered mine from EE 13th Feb and received on 10th March but I was lucky to order early.
Samsung have sold out of the 512gb model and production is on hold, a lot of speculation that Samsung may discontinue the 512gb model and keep it exclusive (Samsung official forum)
Most people have downgraded to the 128gb model and received there phones now.
Up to you if you want to wait to see if Samsung restart production or make do with the 128gb one.
