After designing the last board with a ESP32 Devkit, I found there were a few different versions with different pinouts. 

I bought a some of the different boards to try to work out what was what. This is what I found:

Starting on the left, is the basic ESP32 surface mount module.

Next is the 30pin DevKit, this only seams to come with one choice of ESP32 module with the onboard antenna.

Then we have 2 38pin boards in a narrow format, these are available with different ESP32 modules.

On the right there are 2 38pin boards in a wide format, these are also available with ESP32 modules. 

The 38pin boards have the pins in the same order but the different widths means they are not compatible.

The 30pin board has a different pinout. The 8 missing pins are for the Internal flash chip and are not needed.

 The 30pin board are available in bulk packs and so are a bit cheaper than the others at about $2.70 each. 

I'll see if I can design a board which can accept any of these board for maximum flexibility.