A Small number of the EMR VP185 Fleet have also received a few modifications of late including new Woodward Governors. So the VP185 is being improved and made to be an attractive engine. The other issue is on a pricing point, I'm not sure how much Porterbrook will be selling their MTU Engine power cars for, but Angel Trains's prices certainly aren't cheap. Both of these will have played significantly into LSL's plans for their HST Fleet.Available Valentas. 125 Group have some, but those are destined for their own power cars.
Agreed on LSL not wanting to go for valentas. As for why they'd want the VP185s, they are reportedly better on fuel (& oil) consumption and will go longer between overhauls, so would seem to be a natural fit for a charter operation! Don't forget also that the GWR examples are fitted with ATP which as Scotrail are learning is a pain maintenance wise, and the LNER examples are currently all (supposed to be!) in use replacing the ex-EMT sets
Furthermore, if anyone wants to read up on the modifications to the EMR VP185 Engines, I would recommend joining the 125 Group - It has been covered in recent group magazines.