Denford Novamill 1996 Conversion, Hints & Tips Appreciated

[m_c]

What you've listed aren't really BoBs, they're motion controllers. Some will benefit from a suitable BoB to make wiring easier.

In your photo, the blue board is the motion controller, and the red board the stepper drivers (I think it also provides the analogue output for the spindle). So if you were to remove both, you'd need to install new stepper drivers.
You could either go for individual stepper drivers (Leadshine of some form, or Gecko G251s would work), or if you were to go the KFlop route, you could add the KStep board which includes 4 stepper drivers, as well as 12-24V inputs.

One thing to remember, is if you do buy from outwith the EU, you'll have to pay import tax/VAT/customs charges.