i want to delete the

channels so my sons cant access then accidently. i delete them manually but they keep appearing back. by looking at other threads there is something in 'expert setup' i need to tick or untick. the trouble is i dont see that option on my box.
heres the otions i have:
Communication setup
ngrab streaming setup
software update
remote control
factory reset
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< infobar timeout 6 sec >
Serviceselector help buttons
show sat position
enable fast zapping
skip confirmations
hide error windows
auto show toolbar
show remaining time
use http authentication
dont open serial port
auto bouquet change
auto reconect cahandler
disable teletext caching
enable zapping history
enable mhw epg
enable filemode autoplay
thanks for any help!!