Actually you can refer as many as you like for this offer. I got this e-mail from Lucy at PRS this morning:
A bit of clarity needed from the bunker
Bomber by name and Bomber by nature, he just blasts off these emails without the full picture. Anyway he is off today so time for a bit of female explanation.
If you sign up/introduce a new client who deposits and creates a live account you and your client will be part of the crazy September 1st offer.
If you want to introduce more clients, they will also be part of September 1st offer and you will get a £20 referral bonus added to your account for each new client.
If your new clients do the same they will benefit in exactly the same way.
Wish he was off for a week :-)
I am happy to refer people from on here for this offer. The free bet I would receive would be a £20 SNR which becomes available at the end of the month you are referred. Once I got that I will send you £10 by BACS or Moneybookers.