have they all forgotten Milliband?

Have you forgotten Michael Foot, Neil Kinnock?? Do you even know who they are?

I realise most are harking back to the days of Blair but they seem to forget that his actions are very likely the primary cause of Labours lack of credibility in recent years, quite why they want a return to that sort of philosophy is beyond me.

Again, no it's because we remember the history of a fervently leftwing opposition and it's utter ineffectiveness, leading to the misery of decades of corrosive Tory governments.

People want their political parties to be distinct, not just three flavours of Conservative.

"People" aren't living in the real world. The U.K. isn't a left leaning country. To get into power parties need to appeal to a broader spectrum of voters. If you truly believe that the Blair years was just a Tory gov. in disguise then it suggests you don't know what it's like to actually live under years of actual Tory rule. But you'll get to know soon enough with Corbyn as Labour leader.