That's Alan's Deboer 7 foot beast. Alan had the record I think for getting the biggest boat in the smallest car- he used to own a Tardis-like Reliant Robin, but has now upgraded to a Vauxhall Corsa.
Seaview aficionados will know that there were in fact two versions of the Seaview- the movie version and the TV series version. Although the general outline was similar, they had substantial differences, the most noticeable was the movie version had eight windows at the front and the TV-series four.
Moebius recently released the eight window movie version Seaview, and Rick Teskey in Canada does an eight window boat in GRP.