Look on the Diva escorts agency's website, they have a list of escorts who perform tie and tease services with handcuffs. 

If you're more into independents i think Sania Anadia offers handcuffs session, contact and ask her…

https://www.escortrankings.uk/sania-escort-london-186400

Hi

I'm about to visit London. Does anyone of you know a young lady who offers Tie & Tease with real (police) handcuffs ? Outcall prefered.  

Thanks