Ruin entrance to seaside resort (7)
I believe the answer is:
margate
'seaside resort' is the definition.
'margate' can be an answer for 'resort' (I have seen 'coastal resort' mean 'margate' so perhaps 'resort' could also mean 'margate'). I'm not certain of the 'seaside' bit.
'ruin entrance' is the wordplay.
'ruin' becomes 'mar' (I've seen this before).
'entrance' becomes 'gate' (type of entrance).
'mar'+'gate'='MARGATE'
'to' is the link.
Can you help me to learn more?
(Other definitions for margate that I've seen before include "N. Kent seaside resort" , "Kentish Town?" , "place in England" , "coastal resort" , "resort town" .)