Where is the portrait of sir radcliff?

[Suporex]

it is in the middle of the passage that skeleton sits in (little bit further than a entrance to middle room)

[Gatts]

Yep - so if you continue to go down the same passage where the sceleton is, you will pass the royal bedroom, soon you will see that the color/type of the walls start to change, on your left will be small dead end with two torches (both work in the same way) touch any of these torches.