Order of switch-on makes no difference

No, I've tried all permutations of switch-on order, even leaving long pauses, and it makes no difference. The change in source happens about 10 sec after the HT is switched on or, if later, after the TV is switched on. It makes no diffenerce whether the Sky box (which of course is not Anynet+ compatible) is on or off. The problem seems to arise from the "handshake" between HT and TV. The HT changes source even if it has a perfectly good active signal on the source it is already on. And even though the inevitable result is taht there is no picture on the TV at all - only the blue input screen generated by the HT.