I isolate the individual odours attractive to my flies from a complicated blend using a process called chromatography. Although this is done at Rothamsted with a fancy piece of equipment the basic principle is very simple: you have two different substances or "phases" which have different affinities for the different components of the blend you're trying to separate. The mobile phase, a gas or liquid, is passed over the stationary phase which could be a polymer or wax. Things with a greater affinity for the mobile phase will spend a greater proportion of the time in it, so will come out of the system faster than things with a greater affinity for the stationary phase. Use a long enough system and different constituents of a mixture will reliably come out separately, one after another.
The random chemistry lesson comes courtesy of a brilliant demonstration of the principles of chromatography that I saw at Gatwick airport on the way home. A mixed crowd of Gambians and British people got off the plane and started walking through the terminal building. We all walked together until we reached the first moving walkway, which interestingly the British people got on but the Gambians didn't. Three walkways later, the airport-sized chromatography system had acheived perfect of a mixed group of human beings on the basis of nationality with the Brits emerging 50 metres ahead of the Gambians.
So now I'm home, with my bloke and my family and my knitting and my tea and my 24 hour amenities and I'd be lying if I said it was anything other than a huge relief. Apologies to everyone I haven't been in touch with yet, I've needed a little time to recover but I plan to get in touch with all of you very soon. And everyone I have managed to speak to, even if it's just on facebook, thanks for the lovely welcome.
I think Hounslow Borough Council also wanted to welcome me back, I got home to find this poster on the bus stop on our street!