I am really not suprised by the figures you got...
The clios were always notorious for producing substantialy less HP than declared...the power actually varies from arond 145 hp all the way to 175, so its a matter of luck really if you get a good or a bad one...
mine 5-year old mk1, with 50k on the clock put out 162.1 at the fly, but i have a bad (slighty burned-out clutch) and i ran it on super98 gasoline at the time, so with a new clutch and super100 gasoline i estimate it should be putting out a bit more...
still, i wasnt aware that the transmision losts could be so massive - 27% is quite a lot, as the average losses vary around 20%...