8. a. fortify, shore up (9) _ _ _ _ _ O _ C _
18.a. clear and open nature (12) _ _ _ _ _ _ _ _ NESS
23.a. design plan (9) _ L _ _ _ _ _ _ _
2.d. falsify, corrupt (10) _ _ _ _ _ E _ _ _ _
4.d. render insensible to pain )12) _ _ _ E _ T _ E _ _ _ E
10.d. popular breakfast cake (6,6) _ _ N _ _ _/_ _ _ _ _ _
17.d. one who moves from country to country (7) _ _ _ _ _ _ _
Most of these have been answered in Crosswords so if you don't get all the answers here then you can just do a quick AB search.
I recall 10d was danish pastry