If you have little experience of three phase, try and find out more about what is required as this will have an effect on your over all installation.
For example do you require any contactors for switching high loads?
Any timers required?
How long will the equipment be running for?
What are the start up currents likely to be?
When will the equipment be run?
Whats the location of each M/C?
At least then you can assess the bigger picture. Balancing loads and pin pointing any future potential future problems is all catered for at the design stage.
Personally I would be looking to supply a number of 3P distribution boards, dependant on the maximum demands of the system and divided into sub-mains around the workshop. By doing this you could cater for expansion (i.e. any extra machines) and minimize any disruption when faults occur.
Again a small 3P board could be used seperately for the office block which would cater for any further added circuits and aid with better balancing of the overall system load.
In my experience, offices and factories are always adding / removing circuits over the years. A better design will cater for the potential extra's.
Hope this helps!
The better you map it out the cleaner the system will be.