In OTL, Kent was reportedly the wealthiest of all the pre-English Kingdoms of Britain up until the loss of Lundenwic and the Kingdom's conquest by Mercia and later Wessex. The King of Kent even held the title of Bretwalda for a time.
Your challenge is to keep a 'Kentish' identity as, if not its own state, a genuine form of 'nationalism' akin to that of the Welsh and Cornish. Perhaps play on Kent's Jutish roots in contrast to the Angle and Saxon heritage of most of England.
Bonus points if Kent can stay independent of other English or foreign powers for at least a century longer than it did in OTL.
And yes, I realise this borders on ASB.