I eat a lot of fish and monkfish is one of my favourites. I have a really great local fishmonger and he's great at suggesting alternatives if he doesn't have any monkfish, so perhaps you could talk to your fishmonger. Mine also stocks frozen monkfish (apparently all the local restaurants buy it from him!), its half the price, although it not as good in quality. It depends what you're doing with it, if you're using it in something like a fish stew or fish curry then frozen is absolutely fine.
I don't know what the recipe is that you're talking about as my magazine hasn't arrived yet but its usually used when a firm texture is needed to that it stays together.