Actually it was a Meakes of Marlow Sealion owned by an ex-Met Police Superintendent who lived about a half mile along the sea front. He was in the Royal Temple with his wife every night winter and summer without fail. He's been dead for a few years now.Really enjoyed that,thanks for posting.
Didn't spot the old Thorneycroft Sealion that used to moor there that I always hankered after!