If you want to transit through the Southampton zone, call them on 120.225 Similarly for Bournemouth call on 119.475
Occasionally, if you are going from one to the other they will hand you over.
Though they have received some bad press in the past, the Southampton guys are always unfailingly helpful to me. They do seem to have a knack for identifying bimblers and keeping them away. Provided you sound professional, follow instructions and go where you say you are going to go you should have no problem.