in 1894 Browns directory http://www.ee.surrey.ac.uk/Contrib/manx/fulltext/bd1894/do_ab.htm
Britain Joseph, Britannia House, 4 Clifton-terrace, Broadway
possibly he named it ? names look suspiciously alike! but address not quite same
if post c.1880 then plans etc would be with Douglas Borough Council
There was also a Britania House 64 Loch prom which was a boarding house run by R Londsale (these houses built c.1880) - sse http://www.ee.surrey.ac.uk/Contrib/manx/cd_only/advboard/do_98.htm

IsMarina DR actually Church marina road and the hotel are thus by side of Sefton - if so built c.1890 I think