Iv even ripped the bag off it and started again making sure to be carefull sticking it dwn to the gum but still the same 

iv tried abit of everyone's advise iv enveloped the part which seemed so much easier to make sure there's no wrinkles as I take the protective tape off the tape and iv put peel ply on every part of the mesh that's cut.so iv now pulled vac onit and iv got to 29hg better than I had b4 and when I turned off the pump I couldn't hear one leak  iv just gotta do a drop test now but I got a good feelin