In a thick-based pot melt the butter, add the flour and cook until crumbly. Stir in the fish stock slowly and allow to simmer for 30 mins, stir continuously.
Meanwhile slice the bacon into strips, dice the onion, celery and potato into even size cubes.
Bring the oil up to temperature in a thick-based pot, add the onion and celery and cook until tender. Add the potato, corn kernels, thyme, oregano and curry powder and cook until fragrant.
Deglaze the pan with a little of the stock or white wine.
Add the stock mixture to the above and bring to simmer.
Add shellfish and fish and cook until fish is just cooked then add the oyster sauce.
Recheck seasoning and serve with thick chunky ciabata or french stick.