Thanks for all the suggestions on this one, lesson here to be learnt is never assume someone else has done things correctly lol

As I said in the first post someone else had started the job of replacing the electronics on this machine & then disappeared, spent a bit more time with the machine on Sunday & made some discoveries that I hadn't considered before because I assumed things had been done correctly.
Motors seemed to be far to cold so had a look at the dip switch settings on the drivers & apparently they hadn't been set at all, amps were set at 0.6 lol
Altered that & while waiting to see if the drivers warmed up at all I brought up the diagnostic page within mach3, the home switches were all flashing on & off randomly & if you pressed one it lit up but still flashed on & off a little. Killing power to the motors sorted the problem & further investigation revealed that the motors had been wired with trailer cable. 7 core cable with 4 cores being used for the motors & 2 cores for the home switches. Disconnecting the home switches seemed to stop it tripping the 2 drivers.
So now there is 4 core cy cable on its way for the motors & I have shielded twister pair which I will use to re-run the homing switches.
Hopefully once that is done it will run without any problems lol.