Would recommend getting a test date well in advance, then booking Travelodge Portsmouth - got my room for £25 a night, bargain.
They've got a bar also if you want breakfast etc.
Another quick note about the speed/distance/time questions. They are all devised so they are relatively easy to work out (you won't be asked distance for an aircraft travelling at 438 mph in 23 minutes, the question would probably be distance for 400 mph for 20 minutes... you get the idea).