We just got mothercare own brand cupboard locks (they are suitable for drawers too) they seem to be working. Left one cupboard unlocked with all dd's plastic stuff and tupperware etc so she is allowed to play in that one.
we have the ones from mothercare (can get them from elsewhere.) that stick on. coz i wasn't keen on damaging doors on new kitchen with screws.
worked fab. stuck on really well. needs two bits to be pressed simultaniously. so good to keep kids out. and come off without leaving any marks. can be used on top,bottom,side. handy if you wanna save bending .