If it is the car sold to Mr Smith of Hendon then it is the first customer kit sold. This is referred to in the Midas newsletter that can be downloaded from the Midas Owners Club website
http://midasownersclub.co.uk/downloads/ Select archive cd > Bronze mk1 > brochures and ads > newsletter 0979 p01.jpg
I believe that Neil's car JEH448V was the first production specification car built by the factory - the previous car CNC297T was the first prototype so may have had some detail differences.
JEH 448V may have been given the chassis number DO10000 retrospectively (most chassis number sequences start at 1), or it may have come out the mould before Mr Smiths car. Whatever, it would still have been under build in August 1979 if it was registered in October 1979. If Mr Smith's car was bought as a kit then it is highly probable that he was still building his car and didn't get it registered until after JEH448V.
There was also a chassis number D10001 that MOC records say had the registration number FNT349V and was also White like Neil's car.
I don't know what system Harold Dermott used for issuing the chassis numbers. Did he issue the chassis numbers when the cars came out the mould? when the customers collected the cars? or when the customers were ready to register them? If it was the latter then it would explain the confusion as to which was the first production Midas.
I had previously commented on this on the Facebook page, but annoyingly the thread has been removed.