Former British royal house (7)
I believe the answer is:
hanover
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">former british royal house</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hanover that I've seen before include "Royal house of Britain 1714-1901" , "German 22 Across" , "old house" , "9 [HOUSE]" , "10 [HOUSE]" .)