I could be very wrong, but I thought the interest free loan could be used to partially finance a car, as well as fully finance one? So a £28K deposit funded by the Scottish government at 0% and the rest on PCP from Jaguar Finance. It should still be cheaper than taking the whole lot from Jaguar Finance. And definitely shop around for discounts on the iPace. Drive the Deal have some almighty discounts at the moment - £17K off a 400HSE last week if I recall correctly.
The Low Carbon Transport Loan a.k.a.
interest free electric vehicle loan in Scotland was previously only available for cars on the PiCG list. For the 2021/22 financial year they decided not to follow the reduction in PiCG and still apply the £50,000 limit that is roughly equivalent to the old PiCG (except I think it's on total price, not base RRP less options like the PiCG limit). They have their own
list of eligible vehicles this year as the PiCG list is not sufficient any longer. The I-Pace doesn't appear given it costs more than £50,000.
The total loan amount available through the scheme is £28,000, but as you noted it can be used as part payment either with your own funds, or with hire purchase or PCP on the remainder subject to the total price being under £50,000.