arghhhhhhhhhhhhhhhhhhhhhhhhh

You have no idea.... that sounds like the most mind numbing thing ever!!!! Just addles my brains!!!
It's not that difficult really. A combination lock works using spaces - the three number combination means there are three spaces. If you can work out the relationship between the numbers in the outer ring and those in the inner ring, those spaces should be easy to spot.
Looks like a broad hint is needed.
All of the numbers in the outer ring can made using the numbers in the inner ring - except for three.

34 is one of the numbers, but 3+11=14 and 12+7 =19.14 19 34 ?
Not far of the mark - this was one of the goodies out of my P6 early finishers bag...Reminds me of an 11+ problem
<Yorkie grabs coat shrieks and runs off stage right>
Sorry - had forgotten about this...
Sorry - had forgotten about this...
Pair any two numbers in the inner circle then look for the answer you get in the outer circle. If it's there, cross it off. Repeat that until there are three numbers in the outer circle left uncrossed - those are the answer.
34 and 11 yes - but 19 can be made by pairing 12+734,19,11 ?
That's them - much to yorkie's relief.34,11 and 28 ?
Cheers BB. Seven of what added together earns a type of sparrow ?That's them - much to yorkie's relief.
Over to you.