James Watt, the BrewDog founder who sold the debt-laden “punk” brewer earlier this year, is the subject of complaints to the UK’s data privacy watchdog linked to his surprise bid to buy the company back, the Guardian has learned.

BrewDog’s brand, intellectual property, UK breweries and 11 bars were sold to the US cannabis and drinks firm Tilray in March for £33m, in a deal that rendered the shares of more than 200,000 crowdfunding investors worthless.