Eveything is on hold today - the Building Control inspector has come out and said that the foundation trenches need to be 2m deep at the rear due to the proximity of the trees behind the plot. They need a meeting onsite with the engineer to discuss before any more work can be done.
Now I need to find out why, having paid my engineer to design my foundations, this wasn't in the plan from the start.
Time to put those steel toe-cap boots to the test.