Gareth Southgate and Pep Guardiola will be left wondering what could have been after Cole Palmer’s latest superstar display for Chelsea in their 4-2 win over Brighton. It was nearly four years ago to the day when Guardiola handed a fresh-faced Palmer his professional debut for City in a 3-0 win away to Burnley in the Carabao Cup. In the ensuing years at the Etihad, Palmer showed glimpses of his talents when given the opportunity. But Palmer grew tired of the lack of minutes under Guardiola and didn’t think twice when Chelsea came knocking 12 months ago. Leaving a side that, at the time had jus…