Better than Wagamama Chicken Katsu curry is exactly what this is. Wagamama really does a good Katsu curry, the only downside of their restaurants is that they are not all halal/kosher unless you live in London.
I don't actually know their Katsu curry recipe but I have managed to create my own recipe which tastes just like theirs and even better.
When I put the recipe together I went over it a few times and in the end I was so impressed how simple the whole thing actually was. So if you are a big fan than I hope that you try this.