Since I have been trying to find an answer to my question on the Internet all day, and have found the same question heaps of times from other people but no helpful answer, I have actually tried my own solution and it works great. So for future reference anyone trying to fit an IKEA ceiling light which doesn't seem to have as many places to put wires as the old fitting you take down, I suggest buying a 50p plastic connector and connecting the 3 reds that won't go anywhere else to that - it even fits inside the light fitting.