Just out of interest what would be the easiest engine to put in a 2002 sei ms sporting? Is a full wireing loom job or will the stock one suffice?

1.2 8v Punto should just fit. Your loom will work, ECU should cope.

So literally just swap the motor and all os well? Think my car has a micro ecu. Is that ok?

Micro ECU is crap, but all the Mk2 Punto 1242 8v engines had them too, + canbus.