As 1053 was used for driver training its movements were hard to predict which made it difficult to photograph, so if you're in a car (more so if you're a passenger!) and see it coming the other way you take your photograph because you can. In the process a rarely-recorded section of road is captured for posterity.
The instructor seems to be relaxed about the capabilities of the trainee driver, if that is the correct assumption of their roles. The advantage of using a Bristol LH for training was that it had a clutch and manual gearbox allowing the driver to get a full licence - just about the whole normal fleet had semi-automatic or fully-automatic gearboxes.
