Like a grand house – one in La Plata, possibly (8)
I believe the answer is:
palatial
'like a grand house' is the definition.
I can't tell whether this defines the answer.
'one in la plata possibly' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'possibly' indicates an anagram.
'la'+'plata'='laplata'
'laplata' anagrammed gives 'palatal'.
'i' placed within 'palatal' is 'PALATIAL'.
Can you help me to learn more?
(Other definitions for palatial that I've seen before include "Luxurious, stately" , "Sumptuous and spacious" , "(Of building) spacious and grand" , "Stately, imposing" , "Sumptuous, like a royal dwelling" .)