So I've made my base and spice oil.
I was just wondering if I as t make a Madras using a recipe of this site ( like CA Madras recipe) could I replace the chicken by using fish instead? Something like Monkifish or River cobbler

Or won't the recipe work?

Monk fish is a good choice for a Madras.

BIR style is to deep fry chunks of fish for 2mins then add it to the curry
as you would precooked meat.

Follow my recipe and technique and you won't go wrong.
https://vimeo.com/33663388
cheers Chewy

Could also use king prawns, excellent in a Madras.

I've had some salmon tikka in the past and loved it. I am marinating some tonight after I pull out the chicken that's been marinating for the past 52 hours.

I was going to grill the salmon. Would you say this is a good enough approach or should I fry/deep fry it instead?

I use Pollock fillets (skinless and boneless). They are very cheap when bought frozen. They hold together well when cooked in a curry. I also use them in paella.