Several photos of the two experimental Mini prototypes built and used for testing from October 1957, have appeared in the various Mini books over the years except for this worm's-eye view pre-front subframe photo which is rarely seen. (Note the lack of fins on the smooth gearbox sump casting). At least I have only ever seen this picture in the early 1960's "Mini Story" book by Lawrence Pomeroy. They were nicknamed "Orange Boxes" disguised with Austin A35 grilles and mainly tested at night. The under bonnet photos clearly show the 950cc A-Series engine mounted the opposite way round to later production Minis, reasons for the change were given as carburettor icing and weak A35 gearbox syncro problems. The changes required the addition of a third drop or idler gear and also changed the cooling fan from sucking air in, to pushing air out into the other front wheel arch more efficiently. The 950cc engine was also reduced to 850cc to keep top speed down relative to the early braking power available at the time!
The battery was up front but was later of course moved to the boot. (see underbonnet photos below)
I asked the late Jack Daniels (Issigonis Draughtsman) what had happened to them a few years back at a Gaydon Mini event. He was pretty sure BMC scrapped them both in the early 60's along with the XC9003 wooden mock-ups.







Views of XC 9003 wooden mock-ups:

 

Is that from Rob Golding's book.................

 

Great reading, thanks for posting it!