So I can just change the barrel and as long as I also change the small black immobiliser box with matching one, I don't need to worry about ECU, is that right?
Also, just read this somewhere, doh! 
"Whatever you do, don't lubricate the lock barrel. As the lock and key wear, metal filings can collect inside the lock. They are designed to be self lubricating (brass inside). If you add a spot of oil or WD40 you risk the metal filings being drawn up inside the lock and causing it to wear. Also, because the main starter feed works off the switch it can start to smoke if oil gets into it!"
I poured quite a bit of oil in there! Doh!
