I haven't heard the ordinary gr04 version only the gr04 flagship, which I compared to the VSD1 somewhere in this thread. I assume that R04 will be about the same at least in sound signature, so it will be mid-forward, with less bass and lacking a bit in extension on both ends.
I'm not from UK but as it comes by standard mail I assume you'll have to check your local post office site if there's a track and trace service on their website or what is the most likely thing to happen - check the tracking number on the parcelforce website as they'll be probably handling the delivery.
I already said I like the VSD1 more. gr06 is pretty mid-forward in comparison and also warmer. Of course, I haven't heard the gr06 in a while, so I can't do a 100% accurate comparison in the bass department. As far as I remember the gr06 was softer on the impact and less punchy. The VSD1S' bass on the other hand hits harder than both and is flatter with a bit less emphasis on the mid-bass