When I visited Liverpool, it was not on the list. I hope they have put up signs to show the things mentioned in the explainations why L is on the list.
I agree with Ian Cade that L doesn't seem to be exeptional enough. I hope they can restore the splendour of the buildings that are there but often is in a bad shape. Many nice details are to be discovered everywhere and when in L, don't miss going to Port Sunlight which I think is a nice Garden Town nearby.