You will want an IGC logger for badge claims, starting with silver. The Cambridge kit should be good for this, but you need to check you can obtain suitable files from it.

If not, the cheapest solution acceptable at silver is likely to be a flight recorder such as ? FR100. And if you get a Flarm unit that may include an approved logger depending on version.

Is the Kobo connected to the LNAV to obtain airspeed and vario data? Flight computers calculate wind more accurately, and the final glide information is therefore more accurate, if they have airspeed data.

XCSOAR on Kobo is a superb in flight information system. But do work hard on the ground to understand it as well as possible