In the Half Yearly report Kleos said the expected operational...

In the Half Yearly report Kleos said the expected operational date for the Vigilance mission was Q3 2022, and in the October Update that commissioning is nearing completion with 3 out of 4 satellites to be in formation in November.

The Kleos concept is based around a cluster of 4 satellites which are supposed to provide greater accuracy and resiliency.

They say on their website:

"OUR CLUSTERS OF 4 SATELLITES PROVIDES INCREASED ACCURACY WHILST INCREASING RESILIENCY.

In the case of an operational anomaly, our clusters can continue to collect data with three operational satellites."

Having 4 satellites in a cluster is supposed to give Kleos a greater operational ability/advantage than only having a 3-satellite cluster. Compared to Hawkeye360 for instance who operate clusters of 3 satellites.
Hawkeye360's 4th and 5th satellite clusters began operating in July this year. Their 6th cluster is due to lift off in December this year...
However Hawkeye360 is about two years ahead of Kleos with their satellite launches, as they launched their first one in 2018. They do seem to have reached a greater degree of operational efficiency than Kleos at this stage.