After viewing the videos of the 230's, I have to say that I am impressed. Hopefully Northern and GWR will be encouraged by the DfT to take a certain number on as I can't imaging seeing a class 195 being used on the Penistone Line.
Should Northern have a 230 trial then the Pontefract, Penistone, Windermere, Barton, Brig and dare i say Denton lines would be as good a place to trial it on, as for GWR should they have a trail then other than the Devon and Cornwall branches I do think that the Westbury to Swindon shuttle (when I've used it its been a 153) could also be one service to trial it on.
There's only so much conversions and bi modes that can be produced, I do think that a three car class 230 would be suitble for a 142 replacement as its almost like for like and the way that the North has become busier over the past decade it won't be long before the 150's are converted to four car units since we won't have any 153's or Pacer stock after 2020 unless the 143's and 144's are converted to e14x.