For any departures going south its similar to what Northerner says - Solent call - we "normally" release but then its a guessing game when they actually pop up on radar, so no clearance expiry unless we pass one (heard it done twice that I can remember from the last 8 years!) and any outbound/inbound conflicts is generally done by Solent Approach usually with a call to us for a higher or lower level for one.