The public detest the current system with the only beneficiaries being the scum secondary ticket agencies and touts. Making it illegal to sell tickets above 10% of face value would be a good start.
If a law cannot be policed, it cannot become law. How would this be funded? Who would pay, and why would they? And what structures would be put in place to stop surcharges that have nothing to do with the 'face value' of the ticket? For instance if I were a 'tout'. I would charge my clients a £36 postage and packaging charge for their £40 ticket, for which I can charge £44 under your law. Thus I still get my £80...
Promoters don't care who they sell tickets to. They turn a blind eye to touting which shows they couldn't give a **** about fans. I wouldn't be surprised if promoters do deals with the bigger touts selling them thousands of tickets for big events.