Good Luck Paul. Just make sure that you lock the gate to stop the Ecu Flasher guy from Escaping when he destroys your ecu,
I have previously replaced an ecu on a 307 HDI and another one Today on a Y17DT Astra due to "Mr Flasher" Wiping the Ecu completely blank during The Reflash.
I Also had a BMW with running problems caused due to chip tuning. ( done by one of the so called Top notch companies )
Perhaps it sometimes works fine, But make sure that they will replace the ecu at their expense if they Destroy it.
I have thought about tuning but Relashing ecu's is a risky business even with dealer software, so using aftermarket software. ?? hmmmmmmmmm
Perhaps others with more experience will have different opinions.