Because the details of his latest deal - signed in Las Vegas a few days ago - are still being worked out, he cannot divulge exactly how much he is getting. But he says: "It makes me rich again. I can't deny that."
Indeed, since Tektronix, the US company that is acquiring his Lightworks Editing Systems, is a $1.3bn-turnover organisation ranked 305th in the Fortune 500, it is reasonable to assume that any slice of the action will better the several million pounds he received when he sold out of the audio manufacturer SSL in 1986.
However, Mr Bamborough, who trained as a psychologist before moving into film making, insists that the real value of the latest agreement is that it secures the future of Lightworks as it prepares to move into fresh fields.
Lightworks develops and produces systems for editing feature films, documentaries and news broadcasts electronically. The five-year-old company is not alone in this field but it is starting to dominate it.
Many of the latest Hollywood movies, including Pulp Fiction and Mary Shelley's Frankenstein, have been made using the system, which was created in Britain. Last month it was awarded an Oscar for outstanding technical achievement.
The company is based in Soho Square, London, and has offices in Manchester, New York and Hollywood, as well as a manufacturing plant in Reading. It was founded in 1990 out of Mr Bamborough's conviction that recent developments in computer technology could revolutionise the way films were edited.
Usually this involves either physically cutting and taping together sections in the case of traditional film, or copying from machine to machine in the case of video. Both methods, particularly the video approach, are cumbersome and time-consuming.
Random-access editing of the kind offered by Lightworks transforms this process by allowing any part of the picture and sound to be accessed immediately and put together any way the editor chooses.
This means editing is reduced to its essence - making decisions about what to see and hear and when - without having to bother with cutting, sticking, copying and waiting.
When Mr Bamborough first started toying with the idea he envisaged spending £250,000. In fact, it used up about £2m. Soon, however, that investment looked small, since the company began producing about 60 of the machines a month, at approximately £35,000 each.
The system has attracted hundreds of buyers in production companies handling television news, dramas, documentaries and commercials, as well as Hollywood studios. The secret is its user-friendliness, Mr Bamborough believes. His experience of the film world has enabled him to cater better than his rivals for the average computer-phobic editor.
The system is essentially a processor unit, 20-inch graphics monitor, console and sound system and is compact enough to be taken on location.
The agreement with Tektronix was prompted by Mr Bamborough's awareness that the niche he was operating in would go away as the technology became cheaper and faster.
Lightworks was starting to shift from film into the broadcast arena, but it was conscious that it would be difficult to survive there as a small organisation of about 100 people and £20m in revenues. It had tentative plans for a stock market flotation, but saw in Tektronix an organisation that thought the same way as it did.
Tektronix, which is based in Wilsonville, Oregon, has a long history of innovation. It has recently hired Lucie Fjeldstad, former IBM multimedia chief, to run a division aimed at the video information market. It is expected that Lightworks' editing systems will be integrated with Tektronix's disc storage, networking and archival systems.
Under the terms of the stock swap, Mr Bamborough and key members of the team he has built up will be tied into the company for at least three years. But, since they too will be getting a share of the spoils, they are not complaining.