Need help with finding recent and previous dates based on multiple criteria.

Evening all,

I'm trying to resolve an issue i have with noting the most recent date of a test and also the one prior to the most recent dependant on location and test type. I require most recent and previous test info to enable a comparrison to be made. All other dates are not required but need to be kept as historical data and can't be deleted.

Is there anyway i could get column E to auto populate and amend itself as more test dates and locations are added to the list?

Thanks

Screenshot from 2014-04-29 22:00:58.jpg