Design of house in Dorset our failing (5,4)
I believe the answer is:
tudor rose
'design of house' is the definition.
'tudor rose' can be an answer for 'design' (I have seen 'floral design' mean 'tudor rose' so perhaps 'design' could also mean 'tudor rose'). I am not certain of the 'of house' bit.
'dorset our failing' is the wordplay.
'failing' indicates anagramming the letters (a failed spelling of the word).
'dorset'+'our'='dorsetour'
'dorsetour' with letters rearranged gives 'TUDOR ROSE'.
'in' is the link.
Can you help me to learn more?
(Other definitions for tudor rose that I've seen before include "Flower badge of Henry VII" , "Royal emblem" , "hybrid flower" , "floral design" , "royal badge" .)