Dorchester Trinity Club is in the centre of the town of Dorchester. There is a large car park nearby (free in the evenings), and some on-road parking just outside.
It doesn't look very big from the outside, but inside you'll find a large, recently refurbished ballroom with a large wooden dance floor, and a raised seating area with lots of comfortable seating. There is a licensed bar (with decent prices!) so please do not bring your own drinks. Map