Missed a few bits of information off the above

Airbag sensors been checked below both seats, seems this very common fault where the sensors get either replaced or hard wired has already been done before i purchased the car.

The Sony entertainment system ALWAYS holds all radio presets and never asks for the code unless the battery is disconnected.

The new battery is not losing power so nothing is draining it. (Which was a suggestion a couple weeks ago on another forum)