Just thought I would bring this thread back to life to tell you what happened !
Today I got my hands on another CECHL03 model that I tried to downgrade but right from the start I had no picture and would no let me enter recovery screen. So I'm thinking I've bricked it. Took the clip off and put HDD back into mobo and thankfully everything was OK.
On close inspection of clip I saw that there was slight damage to the softboard in the middle.
Then I thought to myself about the ps3 that I thought I screwed last week and wondered if the faulty clip was causing the black screen issue and not letting me enter recovery menu. So I have just put it back together and would you believe it it works.
Here was I thinking it was a perm brick.
So the PS3 that I unbricked using the Prohack guide did work it was a fault on the clip stopping the display on the screen and the recovery menu.
Just ordered another clip, just got to wait now.