Derek Bryan & Sons No.7 regulator was sold these rooms, 13 April 2005, lot 109. The design of the present clock's case differs in its arched shape and with the useful addition of a key drawer to the base section. The finish of the movement plates is also different, being polished and spot-finished on this example. No.5's accuracy is excellent; on test it has achieved a rate of well within 1 second per month.