welcome to club ,No permit needed in Poole harbour.
if launching at baiter slip it`s ยฃ15 for all day which includes launch and parking, also includes harbour dues.
bear in mind it is a shallow slip.
As Stuie says turn left (port) as you leave harbour and there are miles of sandy beach.
the training bank is marked by posts on your right, advise not to cross unless high tide very rocky.
Good luck with the fishing.
Mick.