Thanks Furna,
I have followed the procedure I have described two messages back and the log attached.
...
sr: scpi_tcp: Successfully sent SCPI command: ':TDIV? '.
sr: scpi: Got response: 'DAT2,#9000000000 AVEDESC1.00E+075.00E-04', length 40.
sr: session: bus: Received SR_DF_HEADER packet.
sr: scpi_tcp: Successfully sent SCPI command: 'WAV:MAXP? '.
sr: scpi: Got response: '5.00E-04', length 8.
sr: scpi: get_int: non-integer rational=500/1000000
sr: session: Could not start siglent-sds device tcp-raw/192.168.1.6/5025 acquisition.
...
'DAT2,#9000000000 AVEDESC1.00E+075.00E-04' looks a concatenation of few responses.
5.00E-04 is my current timing resolution 500us/div
WAV:MAXP? if sent separately to the oscilloscope returns 10000000 but I don't see it in the log.