Can't remove Fuel pump assy?!?

Hi,

I'm in the middle of attempting to replace the fuel pump in my '95 4.2 QS but I can't seem to get the fuel pump assembly out of the tank . I've been in the boot for about 45 minutes pulling and twisting but it just won't come out . Do I need to drop the tank to get it out or am I just missing the technique?

I'll add a pic of were I've got it to in a minute.

Thanks for looking by the way.

Mofri