In the past RATS sold lots of Ascom SE550 programmed to work in the 4m (70MHz) amateur band. No more complete units are available, but Stephen G8LYB has some spares and can offer help and advice to try and get you going again.

Some material which might be of help:
Original instruction sheet with radio |
Latest updated sheet |
Main circuits only |
EEPROM change and other Info |
Other sections to follow, but ask by email if in need now.