PO codes are generic emissions codes from the EOBD system, in other words they are the same for all manufacturers so not that specific. 300 is random cylinder misfire and 301 cyl 1 302 cyl 2 as you state.
Typical "faults" could come from engine mechanical, wiring, fuel, ignition systems - very general!
I will be scoping all my sensors tomorrow so I will post the results asap, it may give you some pointers.
Do you have any recent emissions data (from MOT)? Even if prior to the fault.