Clothes are a form of expression and non verbal communication.
If an employee is wearing several items of clothes that are socially coded as symbolic of 'sexual activity', it should be perfectly acceptable to ask them to dress differently.
Incorporating one of the list (choker, fishnets, corset) into an outfit comprising of more typical clothing could be fine. A friend of mine wears chokers paired with round neck long sleeved t-shirts a jeans. A colleague sometimes wears fishnets with her work suits. The skirts are well fitting and just above the knee and the tights look fine. If the skirts were very short and tight, or if they had slits right up to the groin, the look/expression/communication would be very different.
The 'People Team' (aka HR) in my organisation give awful advice in relation to issues like this due to being ridiculously risk adverse. In this instance they would advise me that I should do nothing incase I upset or offend the person with the protected characteristic. In this instance I, as a hiring manager, wouldn't follow their advice - as is my prerogative.
I would speak to this team member about their work attire. I would check their understanding of clothes being non-verbal communication. If needed (if someone is autistic of has learning disabilities) I would explain this.
I would then ask them what they want to communicate through their clothing. If their answer was appropriate to the role, I would then give them feedback as to the ways in which they are missing the mark, and would advise them on how to achieve their goal.
If their answer was off the mark (if it was based on anything outside of doing the job effectively) U would point out that the work place isn't the place to achieve these ends.
If their answer featured a protective characteristic (religion or gender reassignment), I would return to the question of what they are seeking to communicate through their clothing and whether this is compatible with what is needed from the role.
This isn't rocket science, it isn't even close ti breaching employment law and it doesn't need to be combative or all that difficult.
Just like the whole 'sex is complex and a spectrum' nonsense, this isn't a complex idea once you remove ridiculous 'bring your whole self to work' crap and the idea that giving negative/developmental feedback about performance is abuse/traumatising.
I am a mother, it forms a significant part of my identity, yet I don't seek to parent colleagues and patients. I have also, in the past, done things that, unbeknown to me, weren't the most effective way of working. My managers have fed back and given directives to change, I have then done so.
Very rigid social norms were oppressive and overly restrictive. Most secular people feel that relaxation of norms has been a good thing. Most are easily/lazily accept claims that 'oh, that's just a legacy of Victorian thinking'. However, when engaging their brains, they will quite readily say that the goal should be to broaden norms where there is no good reason not to, not to dismantle them altogether. Many seem to think 'queering' refers to the former, not the latter.
I expect this post is too long to be interesting. Once I started I could't stop!