You haven't told us how many are playing Jez. I'll assume its 6 handed.
If that is the case then I would make a pot sized bet but proceed with caution.
I guess like HiLo the rookie mistake would be to chase half the pot and the one straight looks vulnerable if the third heart comes down.
The first hand too could be in danger as any two turn/river cards could make your hand second best.
It happens a lot in 5 card Omaha that the nuts on the flop rarely are by the river so in 6 card
Bet and hope to take the pot there and then.