Sorry. There appeared to be at least one of each colour. I drove the Wife to Manchester for Gold 6 plus 64gb & that was actually a blessing in disguise, as I'd reverted back to a preference for the 6 however, having had a play with her 6 plus & more importantly, trying it in various coat & trouser pockets I opted for the big one - in Grey.
Keep trying & I'm sure you'll get one. There was at least one of each colour when I placed my order so, you must have just missed out. The trick seems to be to continuously press the refresh button & logon as fast as you can!
I was actually prepared to travel wherever I could get one tomorrow - Exeter, Plymouth, Aberdeen if necessary as time was running out fast - I'm back at work in a few days time.
Time for bed now as I'm up at 05:00 to take the other half to work. I've rather stupidly selected a collection time of 10:00 to 11:00 so, I don't think I'll dare go back to bed in case I sleep in.