Firstly inflation is still over the 2% target and shows no sign of coming down - an entirely self-inflicted own goal caused by the post-Brexit drop in Sterling.
Secondly, the UK is primarily a service economy, and Brexit will devastate large swathes of the service industries.
Third, this is a standard talking point, and is unsupported by facts - one reason (there are others) being that increased import costs for physical goods from tariffs and a declining currency balance out any possible gain from extra income.
Fourth - I don't think trying to turn tax avoidance into the UK's primary economic activity is a terribly good idea. You may disagree, of course.
Scotland will indeed walk away. Ireland will... change. Gibraltar will turn into even more of a mess than it is now.
And so on.
There is in reality absolutely no upside to Brexit. Except for traders shorting the pound, there are no non-imaginary opportunities - only massive costs and disruptions.
And propaganda and PR won't change that. There's certainly been an uptick in British flag waving in the UK, but it takes more than that to run a modern economy.
The irony being that Brexit will destroy the industries the UK is a world-class player in - financial services, law, tech research, engineering, science research, and the arts.