I've had this experience too...flying out of Heathrow first to Toronto...you have to take out everything...so out came my SP3, my Nexus 10 and my iPad Air. The security people did not even bat an eyelid. Flying back from Toronto to Heathrow, I went through the same exercise again and the agent at the scanner asked me why I needed three devices. I said, the Nexus 10 is for movies before I go to sleep, the iPad is for reading my reference texts (I am in academia) and my SP3 is for writing my next book and for everything else. He gave me one of the most curious looks I have ever gotten! A few weeks later, I was flying out from Heathrow to Mumbai. Again, no questions at Heathrow, but when flying back from Mumbai, again the agent at the scanner asked me the same question about carrying three devices. I gave him the same answer. But this time instead of letting me pass, he called his supervisor. This guy took me aside and asked me the same question again to which I answered in the same way. He then grinned at me and said that he did not quite understand people like me and why I needed to carry three personal devices. I told him that I was actually carrying four - he had forgotten to count my phone. He just shook his head and let me pass. The look on his face must have been worth at least £10,000!!!
As all this was going on, my partner was experiencing her own problems. She was carrying a Surface 2 (RT) and a Nexus 10 and two phones!
On the drive back from Heathrow to home, we briefly discussed whether or not we should travel lighter next time - at least in terms of digital equipment. We quickly gave up the idea!!!
No! I ain't going nowhere without my gadgets! And, THAT is final!!!
Edit: I don't even bother not taking out the devices. I just take them out and lay them in the bins. At least that saves 30 seconds at the scanning machines!!!