Climb at Cypress Falls park after work. There is good quality bouldering (starting from V0) 2-3 minutes walk from the carpark. Cypress Falls park is a 10 minute drive from St David's.
To get the most out of the trip, you will be able to second/TR 5.10 climbs or have bouldered at least V0 outdoors before (this is not a requirement though :) )