Hello! I went to Warsash so maybe I can answer a few questions.
Parking has always been a bit of an issue at Warsash but I wouldn't worry about it. You can register a car there and park on campus but there is also adequate street parking minutes walk away. You also have access to an 'old mans club' car park on the same roadas the academy.
There are are two buildings for accommodation, Blyth and Shackleton. All Shackleton rooms except the top floor are doubles, but they are nice rooms to be fair with big communial bathrooms. Blyth, if I remember correctly is or partial kitted out with single rooms.