My pug is misbehaving (not turning over, anti pollution fault, engine immobiliser active, among others...

Having studied this fabulous forum I have discovered that I have the battery that is too short so will change that.
I also want to replace the battery to earth and body leads as they look quite corroded and also the battery to gearbox cable (cleaning connections will be done too). Can anyone please supply the part numbers for these and/or a supplier as I'm struggling to find them.
Many thanks in advance.
My naughty mota is a 2006 1.6 16v Pug