The obvious PoD for Labour would be for Brown to run against Blair in 1994. Blair wins, Brown is given a high ranking job within the cabinet, but he is not seen as the heir apparent as in OTL, and a leadership election takes place when Blair vacates the post of PM, and Clarke runs and wins as a Blairite candidate. If you want to have Ken Clarke take the post from him, then you could have Blair resign after losing the Iraq War vote due to KC coming out against as leader of the Tories, as he was when he was a backbencher in OTL. He would have his shares of rebels, but between Labour rebels and Clarke loyalists, Blair loses the vote, leaving Labour discredited and demoralized for the rest of the term, before being turfed out by KC's Tories in 2006.
I am not entirely sure how to make KC leader of the Tories in the first place though with post 1992 or 97 PoD, the obvious thing would be to neuter some of the Euroscepiticism in the Tory parliamentary party, perhaps through avoiding Black Wednesday. But I am neither an expert in Tory party politics or economics, so I doubt I could explain precisely how.