Swaption bp vol time series data retreival in python

In excel using the formula

=RHistory("GBP20YX20Y=ICAP",".Close;.Timestamp","START:01-Jan-2019 END:18-Aug-2020 INTERVAL:1D",,"TSREPEAT:NO CH:IN;Fd",H10)

does not retreive data back to presant day.

Equivalenty using python it returns the same data using the following:

df = ek.get_timeseries(['GBP20YX20Y=ICAP'],

start_date="2019-01-01",

end_date="2020-08-18")

I can solve the excel issue by adding additional parameters (answer supplied by Reuters helpdesk):

=RHistory("GBP20YX20Y=ICAP","BP_VOLT.Timestamp;BP_VOLT.Value","START:01-Jan-2019 END:18-Aug-2020 INTERVAL:1D",,"TSREPEAT:NO CH:IN;Fd",B2)

The question is how I change the python function to bring me back the equivaent of this?

These RICS are the 20Y20Y atm vol on ICAP broker screen

Any guidance would be most appreciated.