[SimonW24]

Hi Mike, 

Thanks for your fast response. I'll have a go.   :-)

Cheers
Simon

Update: I tried entering MIDI data via the built-in translator and also using the sys-ex system. Both worked - at first. 
Unfortunately, I can send about 3 messages successfully before the Helix becomes unresponsive, and I can't get it to work again. 
If I unplug the cable and reinsert it (and give the tablet permission to use it), then the messages work again, but only ~3 times. 
I have looked at suggestions for sending MIDI from a Samsung Galaxy Tab s7+, and have set USB to default to MIDI, and turned off audio over USB. 
I am connecting the tablet to the Helix directly with a USB-C to USB-B cable. I have seen othe people using a special MIDI adapter, but I don't know if these are old sites. 
Any suggestions?
Cheers
Simon