The afternoon training runs have been cancelled to accommodate the testing to find out the fuel consumption problems, vivarail can't seem to resolve it so far.Good question. I am guessing TfW currently use a 150 (four double doors) or 2x153 (four single doors) or maybe 3 if the conductor doesn't want you using that door. Like you I haven't travelled on a DMU service over there, but I struggle to see the issue.
What is becoming apparent to me is the innocence TfW seem to have displayed when signing the Vivarail contract. I genuinely believed Vivarail would have researched the intended operation to the Nth degree, then specced 230006-010 accordingly, particularly in view of Vivarail's experience with 230001, and 230003-005.
Having said that, how much has been changed by TfW from the original plan? Were Vivarail expecting TfW to service the 230s at Wrexham, rather than run ECS to Chester for servicing, but then servicing at Birkenhead, then talk of a depot at Dee Marsh.
Vivarail's USP seems to be the environmental greenness of battery power with increasing ranges being achieved through more modern battery designs. This seems at odds with rumours by some that the TfW 230s cannot manage more than a day without refuelling.
Seems to be a lot of rumour smoke and mirrors
I keep getting told I'm quoting messroom gossip, but the facts are the 230's have been delayed again now it's may 2022 for there introduction.
If vivarail would have done the research you say they did, they could easily see Wrexham is not suitable for a depot. There's no road access / no depot buildings / no fueling point or facilities etc
Both parties haven't done themselves any favours in the project, plus there's still lots of issues to resolve before they come into service in may.