Pointless swopping out the master without doing the slave.
£3200.00 and the fault still not fixed.
Might sound a bit harsh, but as the saying goes: "A fool and his money are soon parted.
You really do sound like a salesman dream.
Hopefully you will have learnt your lesson and realise that the Nissan techs and service personal (at this particular dealership) are a bunch of incompetent morons.
Crack on and lodge your complaint, however unfortunately, you will be pissing against the wind.