TRIP released a load of optimisations at the start of last week (22/23rd July). This resulted in the speed going from slow to acceptable/good. Giving it a time frame it has gone from 10+ seconds per search to around 2-3 seconds.
Since the roll out of the speed increase our traffic has jumped again. Yesterday we were searched over 52,000 times. Looking at the last 3 days we were searched 129,938 times (includes a Sunday). Compare that to the same 3 days in mid June, we had 104,285 searches.
Entirely sensibly, people like speed in searching and have better things to do than wait!