walls of sound is an awful seller on ebay
Are you thinking of Walls of Sound out of Florida? They're not Wallsofsound1 or Wallsofsound2.
WallsofSound1 & 2 is Lee Hunter, in Tenn., one of the top in-person dealers since the 90s or earlier. He's rock-solid.
Mikex, can you post some Marc Bolan exemplars? He's hard to find and I don't know his autograph well but eBay's Wallsofsound1 & WallsofSound2 are Lee Hunter, a highly respected dealer.
PSA Autograph Facts has this one, similar characteristics similar to the one you don't think is real, although the one you called out is signed nicer:
That example is 100% fake
Yes, the OP looks like a sit-down autograph. But see how the end downstroke of the M is straight on all 3. Compare the shape of both Ls in the OP to the Ls in the others. On the first and second pic the B is perpendicular to the base but the L leans slightly to the right. And there's a natural feel to all 3.
Again, I don't know Bolan well, but all 3 of these feel like like they could easily have been signed by the same person.
This example looks atypical imo
Im not by any means a professional authenticator but I like to collect autographs. But unless it's PSA certified I won't by it
No TPA is going to be perfect, but, in entertainment, BAS has the better community reputation of the 3, though, when it's available, most collectors prefer something more specialized.