Dunno if it helps, but a IR Z4MC YC56ZWT went through BCA today for £13.2k + fees of about £500 on top. The car had great spec - cream leather, sat nav, DSP, leather dash, cup holders. FBMWSH. CAP Clean of £13.4k. It was part-exed at Porsche, so another plus point.
My trigger finger was twitching having owned YF06HLP from new, which I sold in 2012 to a mate, but I realised that I needed a 9th car overall and a 4th S54 powered one like a hole in the head, thus I passed...
Seems mkt in the trade is not that strong at the moment - must be pre-Xmas...