Hardly complacent, mate.
even on this SO simple manoeuvre I’d got out, weighed it it up, checked all the angles, got back in, go backwards slowly, mirrors mirrors mirrors, clunk, oh ffs!
That’s not complacent at all.
Numbskull driver came along and parked a car in the blindspot. You cannot legislate for every eventuality. This is a shining example of what you cannot expect on a day to day basis, I.E. an idiot driver.