Hi Dave, the battery voltage measured off load does'nt mean a great deal, you need to measure it whilst cranking the motor over, this will give an idea of the state of the battery internals, as it starts with a jump start it would tend to indicate a duff battery, Halfords etc will do a "drop test" to determine if the battery is on it's way out.
Does'nt sound like a starter or immobiliser problem
nigel
November 2009