Modify the search input to be able to take multiple queries

searching by name and dob is a possible combination. The syntax
"lastName@dob" can be used to search by dob and name at the same time.
hospital_number still works as H123455 etc.

In totality you can search by all three:

name@dob hospital_number
smyth@03/04/1988 H1234523

Spaces are not required, just the @ symbol for the date