To be clear, I'm not a criminal lawyer. Crime is far, far away from my specialism. I am also not your lawyer. This is not a researched opinion. Cheers.
This would absolutely (in my opinion) be a criminal offence in the jurisdiction.
Common assault - includes any non-consensual contact or the causing of non-consensual contact through another object. This could easily be analogised to the cases involving leaving a trap or poking with a stick.
Much more serious:
Sexual assault - SOA 2003 s(3) - AFAIK this includes touching through another object, so the offense would be available
Infliction of GBH with intent - GBH requires common assault (see above) and the rupturing of membranes, which lice do when they suck blood (this potentially hold a sentence of lifetime imprisonment, and is an extraordinarily serious offence in the UK)
The Crown Prosecution Service generally charges less than the most serious crime chargeable, but it is quite feasible to imagine an assault or sexual assault charge being made if this were used. Also, the site owners are doubtless on the hook for all sorts of conspiracy and assistance offences, but I know little to nothing about them. Also, this may well come under the remit of Operation Sapphire (the London police operation on rape and sexual offences. I know some of the outstanding officers involved, they're like dogs with a bone once they get a suspect in their sights.) or could be viewed as domestic violence, which elevates sentencing in the courts (and opens up the possibility of elevation to Crown Court sentencing).
All sorts of wonderful civil options even if the CPS didn't prosecute, with trespass against the person and negligence high on the list.