Thanks for the comments guys, they are wild caught and were imported around 6-8 weeks ago.
They feed heavily on earthworms but turn their nosed up at frozen, I've been advised to marinate their worms with other foods so have recently started doing this and last night watched two of them repeatedly chew white bait and spit it back out so fingers crossed!
My primary concern is getting some weight on them as they are a little skinny at present.
Cut up shrimp into pieces similarly shaped like earth worm. It takes bit of time to do. Than cut up earth worm and let the worm blood and guts marinade the shrimp. Add tiny bit of water and let the shrimp parts and worm parts marinade for few hours.
When feeding only drop a few parts of worms in first to get them all hyper it's feeding time. Give them that first taste of worm so when you drop the marinaded mix they pound it down quick. Once they take to this about a week later try it with out marina ding them but still offer worms first.
I marinate for about an hour now but I'll try doing it for longer and I'll try actually cutting the worm so that the blood and guts gets everywhere, makes sense that the smell and taste is in the blood and guts!