Dealing with the exact same issue in the workshop atm Cause for this one seems to be lack of lubrication grease on the inner Ball joints of theSteering rack but for creaking issues it can be hit and miss in terms of saying it is definitely one thing.
To solve creaking when turning at full lock/ going over bumps (which is where 90% of the issues are)
Remove the strut assembly Remove the top mount replace the threaded bush and grease using lithium lubricating grease. (typically
Ibiza's mk5's)
Remove wheel bearing clean and grease the mating surfaces of the bearing and the bearing it's self (typically mk leons)
Remove the LCA (lower control arm) and grease the bushing (typically mk3)
What I'd suggest you do is Jack the Front of the vehicle up and move the wheel from side to side if your getting the creaking noise I'd start with the top mount assembly.