Peter on tree overlooking river’s very secure (4,2,6)
I believe the answer is:
safe as houses
'very secure' is the definition.
(I've seen this before)
'peter on tree overlooking river's' is the wordplay.
'peter' becomes 'safe' (slang term).
'on tree' becomes 'ash' (ash is a kind of tree. I am not sure about the 'on' bit.).
'overlooking' means one lot of letters go next to another (down clues only).
'river's' becomes 'ouses' (Yorkshire river).
'safe'+'ash'+'ouses'='SAFE AS HOUSES'
Can you help me to learn more?
(Other definitions for safe as houses that I've seen before include "Not in the least dangerous" , "Not in the least at risk" , "Thoroughly secure" .)