How to - shuttering trench to 2.4m plus maybe more

Soon, we will be starting phase 3 of our rebuild.

First we need to demolish and clear existing walls as they have no foundations, but that's easy :-)

Then we need to dig the trenches for this phase.

Straight forward in theory, but this bit of the land has clay so SE has specified 2.4m depth or deeper until we get 'good ground' where they is clay.

These may well be stepped as the existing part of the build is on sand and there is probably another 10m of sand before we hit this pesky bit of clay.

This is a corner to join up with the rest of the walls already rebuilt. Long wall is 18m (south), shorter wall is 9m (west)

There are also some internal walls that will need foundations, but these are very unlikely to be on the clay bit unless it's more extensive than our original trial digs showed.

This means that we will have to get someone in as our excavator is only little and won't go that deep.

Still all okay so far.

Now, what I need to know is how to shutter and brace. All our previous trenches have been 1m so didn't need anything.

Do said shutters need to be removed before, during or after pour and how manageable is this for 2 people.

So, please advise on shuttering and will BCO be happy to look at trench with shutters in place or does he need to see the sides.

In the worse case scenario that we get rain after we've dug the trenches then do we need to wait for them to dry before we pour.

SE has specified type3 concrete, will this 'settle' or do we need to vibrate as it's poured.

Is there anything else that I have totally forgotten that is obvious to consider.