So the cause of the problem turned out to be the M1005 command which apparently is cumulative instead of absolute. As i had it in one of my filament profiles it would add to the skew on each print as opposed to just correcting for it.
This meant that the end positions for the x and y axis were beyond it’s endstops, which I suspect caused the banging and ironically the skew.
Even though i tried resetting the skew and eeprom, what worked was using this command:
M1005 I0
and M500 to save it.
The skew correction macro M1005 is still new on bambu but I think it should have detected by the imu in the printhead and bed that they were clearly hitting their endstops and the skew was outside of the printable range.
Still glad that has been sorted out.
I learnt all this from this form post in case anyone wants to know more or has a similar problem.