Posted: 24/10/2012 at 12:46
Think about water. You don't want to be carrying cans around and a hosepipe ban might make life very difficult. Siting the greenhouse close to the house where you have water butts and mains water would make sense. You might be able to rig up a syphon system to bring water to the greenhouse in either position though.
It is also much more convenient to nip into the greenhouse for herbs, strawberries, tomatoes etc if it is close by. If it is a long trek to the other end of the garden it will tend to get ignored.
As for orientation it really won't make much difference, after all it is entirely transparent. I think the east-west guidance is more relevant to long commercial greenhouses, domestic one's tend to be nearer square e.g. 10x8. Mine is 8x8 so it makes no difference.