Speaking from some ignorance, but it seems that part of the argument is that there is a need for specialised neonatal transport, and that the requirements for this are different enough that a regular HEMS setup won't work. However, whether there is enough need to justify an entire separate machine and organisation to go with it (plus the watering down of charity income for everyone that goes with that) is unproven.
Would it be possible to add to an existing charity, perhaps by modifying the fit so that some extra equipement can be slotted in as needed, and some extra staff are added to the books be a better option? That way, you get the capability for when it's needed, presumably at a fraction of the cost, and you don't dilute the fundraising. I don't know enough about the equipment required for NETS vs. HEMS to know whether this is even possible, but it seems like it's at least worth investigating. Perhaps an opportunity for some tie-in with the medical kit manufacturers?