I did a bit of digging on Project MARSHALL today and the RAF Shawbury, Linton and Coningsby WAM systems are working and intended to provide cooperative surveillance services for RAF Shawbury, Linton‐on‐Ouse, Leeming, Topcliffe, Coningsby, Cranwell, Waddington and Barkston Heath airfields. The RAF Brize Norton and Marham WAM systems are installed and are in the final stages of test and technical acceptance.
From what I was told they are able to receive the extended squitter messages of ADS-B as well as providing Multi-Lateration of transponders.