Nope, but I was in my dealer's on Friday and he emailed the head of the 4C program in the UK to confirm they'd received deposit. Got a reply back while i was there. Apparently they were overwhelmed by the response so it's taking a wee bit longer than expected to get through them all and return them.
I would imagine there was a certain amount of slippage getting people to stump up £16K at short notice, and probably a little bit of passdown going on. Is the sort of sum where a receipt would not go amiss. Has not been 28 days yet, and my dealer is happy it is in order, but perhaps it is time for a 50p stamp or an email just to confirm things are in order