Hi, i have managed to sort mine out now.
First of all i would like to thank len very much as i did PM Him and he told me how to get the pump out, its quite simple.
Once you have done the obvious and disconected the pipes and power conector, you can use a small bit of wood ( i used the handle of a small hammer) Hit the right hand side of the large nut using a bit of wood and a hammer away from you and dont be affraid to HIT! it will come undone with a few heafty wallops. then you can pull the top part off and reach down into the tank where the pump sits, grab it with your hand and twist to the left, its a bayonet type fitting and the pump will just lift out of the tank. really is simple and easy once the nut is off, took me 10 mins to swap mine over.
