An early QL type chassis of 1928 was specially prepared as a show chassis, complete with sectioned engine and gearbox. History hasn't recorded where it was shown (it might just have been a company directors inspection at Bearwood, there are other photos of different complete types prepared for such displays) but I suspect this was either the first QL, chassis 578, which was eventually bodied (Brush B34F BB1033) for the Potteries company as VT 8801, or the second, 579 which became Midland Red 897 HA 3720 with identical body BB934.
The QL was the last of the 'old design' of SOS vehicles, although chassis did not alter much at first after this, bodies did - particularly the curved, rather than angled body sides which the M model introduced next.
The QL introduced 4-wheel brakes to the fleet, and hydraulic brake operation, which was to remain the preferred option until vehicle production ended with the D9 and S23 models in the 1960s.