"Sammy" the seal was a regular visitor inside Chichester Marina. He/she used to stay inside the marina for some time where there was a regular supply of fish. The last time I saw it there, was a couple of years ago.
Joking aside, in the more than 20 years I have been boating in the Solent, both as a hobby boater and in my role as an instructor who is on the water a lot of the time I have seen seals only 4 times. When I was a coxswain for the Portsmouth Harbour Patrol some 3/4 years ago there was a dolphin that played around the entrance to Portsmouth Harbour. He was great, would follow the twin outboard cat with his head between the outboard and would leap and play behind the boat - it was great to see. Unfortunately he was run down by one of the tugs and was heard crying under the piers. it was well documented at the time.
Since then, apart from the pictures I have already posted of the seal in Newtown Creek there are very few sightings. Lets face it, the Solent is very busy and seals are wild animals that seek solitude, so if you see them you are very lucky and I suspect that in the summer they are keeping well away!
We recently took the grandchildren to the beach on Hayling Island. Loads of kids in the water, when a seal swam by, right through the middle of them. No kids came screaming from the water, and the seal happily continued on it's way towards Chi Harbour entrance, no doubt leaving the West Pole to port!!
Seen one two times (once per year!) in Chichester harbour - both times it was on the corner heading into Sweare Deep (towards Hayling bridge/Northney marina)... magical...
We saw a seal near the marina only a few weeks ago. I think he chases the fish up the channel to the lock. I've also seen seals near Langstone Sailing club at half tide.