I've had legal advice from a qualified solicitor and I don't want people offering sex for money on the website. Here's a quote from a BBC report: ?Under the Sexual Offences Act 2003, it is an offence to cause or incite prostitution or control it for personal gain.? So if you create a website purposely for prostitution and you make money from it, you may end up getting into trouble.
Your solicitor is misguided. The SOA is complex and convoluted though, so finding somebody with detailed knowledge of it isn't easy.
The BBC report is correct, but doesn't apply to advertising of prostitution because this does not constitute either incitement or 'control'. Control means doing something that directly results in an act of prostitution taking place (such as answering the phone and taking bookings, for example) but all you're doing is providing advertising space so that people can put up their details and control/gain from their own prostitution which, like selling or buying sexual services, is perfectly legal.
Incitement would be encouraging or even suggesting that somebody who is not a prostitute becomes one - approaching them in public, or advertising agency work specifically for people with no experience of sex work would fall into this category. Again, you're not getting or offering to get people work as prostitutes, you're selling advertising so that those who are already working can do so themselves.
Either way, this statement from your website:
"You will not offer sex for money (it is illegal in the UK)"
is bollocks.