Seat on jumbo had to be turned on using what? (6)
I believe the answer is:
howdah
'seat on jumbo' is the definition.
(I've seen this before)
'had to be turned on using what?' is the wordplay.
'to be turned' shows that the letters should be reversed in order.
'on' means one lot of letters go next to another.
'using what?' becomes 'how' (I can't explain this - if you can you should give a lot more credence to this answer).
'had' in reverse letter order is 'dah'.
'dah' after 'how' is 'HOWDAH'.
Can you help me to learn more?
(Other definitions for howdah that I've seen before include "high chair" , "Does it get you high for a trip" , "top seat?" , "seat on Jumbo" , "Who had a change on the elephant's back" .)