Both the bikes - and those stand on contraptions - were used on a test track.There was a commercial comparison of the two bikes, with the implication they were comparing two road legal machines, which they were not. The implication is there because 1) the volt is a road-legal machine, and 2) the number of people who possess sufficient private land to make a serious and legal market of 25mph bikes, is countable on your fingers and toes. In light of that it's what the ordinary viewer would have assumed from the section.
You may be right that there is no regulatory question but I think you may be wrong too and it's certainly not stupid to suggest there is one.
You may be right that anybody (not just Volt) could have standing to make a complaint about this, however, standing may figure in whether a complaint is taken seriously. It is a principle of many tribunals that you must have skin in the game to make a complaint. I don't think it's a pointless complaint though. A few commenters above have said they feel sorry for Volt and I think the reason they feel sorry is because the bike was mis-portrayed as being the slower of two road legal bikes, which it wasn't.
I didn't pick up any inference from the programme those gadgets or the bikes were legal or not.
Seemed to me the programme ignored that question, therefore it doesn't arise - even if some viewers think it should have done.