As far as marketing is concerned, communication can simply be divided between paid (advertising, web etc) and unpaid (
PR). And again, the simplest view of both is that paid gives you control of the message, and unpaid very little control at all.
A quick look at the old website (in Tony Crook's time) showed little regard for the quality of the paid message. The website, like the showroom, was amateur. There was virtually no advertising attempted, no sponsorship aside from Le Mans, much earlier, in the mid-50s. The little money Bristol spent on controlling the message, they spent badly.
I think it has been argued many times that Bristol, under Crook's stewardship, had masterly control over myth-making. This is the unpaid area of communications.
Yet for much of that, Bristol has Setright to thank. Certainly Tony Crook added some wonderful anecdotes that added to Bristol's image as an eccentric choice. But I am not sure he did much to give the engineering credibility. It was Setright's journalism that helped the marque shine. There are plenty of other examples of journalists who were mostly uncritical of the cars, Martin Buckley's tribute in his Encyclopedia of Classic Cars was one of them.
I am just not so sure Mr Crook and perhaps even Mr Silverton ever understood the subtleties of controlling the message. For Mr Crook, the message was something chaotic and out of control, something he didn't like dealing with and maybe even feared.
I would have recommended Top Gear didn't test the car on tv. The show is deliberately chaotic and you would never know what they would poke fun at. But I would have pushed Bristol to find a 'friendly' journalist, someone perhaps that could understand the technology vs bespoke argument, and someone Bristol could work with to address any quality problems and overcome them. Too often Bristol abdicated any chances of control over the message, or in Mr Crook's case, made the story not about the car itself, but why the manufacturer didn't give access to the car. In any other industry, and probably in this one too, that's just plain suicide.