Don't have to wait 4 years, just look at Beijing 2008 - 19 golds. We're only up 6 from that. Not really that much of a host advantage.
But good effort on the troll bruv.
we also spent more this time with £235 million on olympic sports going into beijing but £264 million for london 2012*. the home crowds and desire to win in the home olympics help boost performances - but maybe also put too much pressure too? - but i think money and sustained investment over time are key here.
* http://www.bbc.co.uk/news/business-19144983
which also has a breakdown into how much we spend on each sport - if you want you can compare swimming and cycling and our returns from the two and weep.