FGW 158s
 

FGW appear to be re-forming their 3 car 15895X units back into their original 2 car sets. 158749 worked the Great Malvern to Brighton whilst 158951 was on the Cheltenham to Swindon service with just 52764 and 57764 but still with its 3 car number.
I assume FGW are reverting to the old 2 car sets to make more of them available as they always seem to be leasing units from SWT and Arriva.

I doubt that it's a permanent thing; the 158/9s are used on the Cardiff -Portsmouth run, where a two-car formation can often be totally inadequate. Having said that, I did photograph 158 952 as a 2-car unit at Fratton last Friday on that route:
http://daverowland.fotopic.net/p63395013.html

Nice images Dave.
mickey