Here's a handy tip if your curry ever decides to curdle on you - and this has never happened to me before.
I was making my usual dhal recipe with coconut milk, when I turned round and it had separated! I didn't even know coconut milk did that. So before I chucked it in the bin I thought I'd try a couple of things. I added a glug of double cream and viola! The sauce was back to normal.
Hope this tip helps if you ever find yourself with a curdled curry!