Presuming you are going to OASC there is a bus which picks you up outside the main station entrance at Grantham and drops you off outside the candidates mess.
The times are. .Mon - Thurs 1125 1255 1425 1555 1720. .Fri 1415 1545. .Sun 1255 1425 1555. .Sat (only when 6th formers are boarding) 1305 1435 1605
It only takes about 10-15 mins depending on who is driving <img src="wink.gif" border="0">