From the M27 Eastbound (from Southampton/Fareham/Winchester):
Head East on M27
Continue forward on A27 (signposted Brighton/Havant/London A3[M])
After 0.7 miles take exit for A2030 (signposted Southsea)
At roundabout (with traffic lights) take 3rd exit onto A2030 (signposted Southsea)
After 1 mile, at first set of traffic lights, turn right onto Anchorage Road and stay in left hand lane
After 0.14 mile, at roundabout, take 1st exit into Robinson Way (signposted Industrial Estate)
After 0.23 mile, at T-junction, turn right onto Airport Service Road
After 0.08 mile, take first left turn into Dundas Lane
Continue to T-junction, then turn left into Dundas Lane
At first roundabout turn left into Admiral Lord Nelson School car park
From the A27 Westbound (from Havant/Chichester/Petersfield via A3M)
Turn left from the A27 onto the A2030 (signposted Southsea) (this is a 3 lane section of road and you need to be in the left hand lane)
Then follow directions as above.