Doh - I may have solved my problem. I'm sending MIDI and not DIN Sync 24.....excerpt from Schneidersladen website .....
Special feature in DIN Sync24 mode: press the encoder while powreing up and choose between a DIN Sync signal with 24ppq or an alternative Eurorack-compatible analog clock with 8ppq (32ths) and a positive reset pulse.
So, DIN Sync it is with a positive reset pulse for Reset ! I'll try when I'm home from the office.