Paul,
You will never be the hero but you may get to be the goat. HAHA. If you work is in an area that has this typical 2m of firm clay over the soft clay your best short term bet is to grab the oldest crane operator at your company and ask him what works and what doesn't. If you have...
Jimbo,
The design of a structure that will cost at leaat a few hundred thousand at least warrants some real soil testing (ie more than Atteberg Limits and a moisture & density test).
I am not sure about the age of the structures that you are looking at. If there are older structures have...