Caverton will be certainly pushed to find EC155 type rated crew with any offshore experience if they canīt entice Bristow crews.
Where are the sources?
ACN - possibly
Bristow Nigeria - maybe (provided they are not on a Shell blacklist!)
Bristow North Sea - very unlikely
CHC NL - no!
COHC - unlikely to satify NCAA
Dancopter - very unlilely if they think Den Helder has to be a rotational posting!
ERA GOM - unlikely to take the leap to Africa
Shell Brunei ex Bristow - perhaps with a bit of pressure!