(Photo by Leon Neal/Getty Images) With no firm denials from Wes Streeting’s team yesterday, Westminster expects the Health Secretary to launch a leadership challenge today. He needs to present the names of 81 MPs who support him in order to make it onto a ballot of party members.  But can he? Streeting’s politics, broadly of the “progressive” or “new” right of Labour, is well represented in the Parliamentary Labour Party and it might have been assumed that in the event of a contest he would easily get over the line. However the chaotic circumstances of the last few days have raised serious questions about his base of support in the PLP.…