MATZ frequencies are on the map - just underneath the word MATZ! - but they don't always tell you who the frequency is (e.g. Mildenhall/Lakenheath CMATZ just says 'CMATZ 128.9', though the NOTAM activated bit for Honington does say 'MAZT NOTAM Activated Lakenheath 128.9' which is more helpful).
Default callsign for a MATZ is 'Zone' e.g. Lakenheath Zone.
Tim