Please allow me to clarify the story regarding the Type 179.
Supermarine drew up a six-engine (probably RR Buzzard) monoplane, Type D in Supermarine's old project naming system, to spec. R.6/28 but this was not ordered by the Air Ministry.
The design was enlarged and modified as a civil flying boat, Type 179, powered by six Bristol Jupiters (see posts #5 and #6). One example was ordered by the Ministry to spec 20/28, but with the engines changed back to RR Buzzards (see posts #2 and #9).
The aircraft was then redesigned completely in 1930-1931; most noticeably the elliptical wing was dropped in favour of straight-tapered and eventually the three twin-engine nacelles became two twin-engine and two single engine (see posts #6 and #8)