 The Phase III, released to the market for the mid-October 1955 Earls Court Motor Show, was a radical change with the elimination of the separate chassis.There was an overlap in availability of the old model with the Phase II estate continuing into 1956.UK fuel was no longer restricted to the 72 octane "Pool petrol" of the 1940s and early 1950s, and with the modest increases in available octane levels, the Vanguard's compression ratio was increased to 7.0