Concrete garage floor

[Cala Sona]

I am extending a single skin block built garage to create a double garage, also using blocks. The ground below about 400mm is free draining, well compacted stony soil, on which I built the foundations 600mm wide excavated to 800mm depth with 100mm hardcore and 100mm x 600mm wide concrete.
I was also going to lay the concrete floor using 100mm compacted hardcore and 100mm of ready-mixed concrete but now have some doubt on whether this is acceptable or not. One builder has insisted that the concrete must be 150mm deep, one has said 100mm is okay!
I contacted my local building control (Scotland) - "100mm could be okay, 150mm would be better. I can't find any specific minimum depth"!
Then I asked the ready-mix suppliers - "100mm should be adequate. We can supply stronger grade (C30?) concrete which will help".
The trouble is that nobody seems to know for sure. Can anyone offer any advice?

[elwood]

Hi.

how about 125mm


Bye

[Cala Sona]

The trouble is that 100mm hardcore has already been laid down and compacted (I should have explained that) and I would wish to avoid digging it all out again or even scraping 25mm off the top then having to hire the compactor again!
Thanks for the the suggestion of using 125mm. I had already considered doing that and it will just mean a slight height difference between the two sides of the garage with a little ramp where the original block wall will be removed.