[neilw20]

Is it in emergency stop mode?
I don't know this machine, but in a lot of machines all of the overtravel limitswitches are wired in series with the emegency stop switch(es).
Any axis off limit, or something else in the emergency stop loop (like a tool changer or turret indexer gone ape) can make it hard to get moving.
Usually only the slow step or slow jog rates are active, allowing you to move the offending axis. Try all of the slow/step positions for manual feed and the jog wheel/buttons. As an example, the Bosch controller I use has a button maked like a switch, that you must hold so you can jog off the limit.
This fault often created by a power hiccup during referencing, then all of a sudden machine is broke.
If during referencing a sluggish home switch allows an axis to overtravel then this will cause same problem.