I contacted BetRegal and asked about having an account with them if you already had one with another Aspire Global site such as Karamba or Goliath. I was told that this was fine, as long as you don't have more than one account with the same site. I pointed out to them that this wasn't my interpretation of their terms and conditions, but they reiterated that there was absolutely no problem.
My guess is that their terms and conditions are just poorly phrased and that you can have an account with more than one of their sites, otherwise BetRegal would be disqualified from accepting any new customers who already had a Karamba account and I can't believe that they would have gone over to Aspire Global if that were the case. That said, I didn't want to open an account with them, so I can't be sure.
If anyone does fancy giving the revamped BetRegal a try, however, they are offering new customers a 'Bet 20, Get 20' free bet deal (although, as ever, check the terms and conditions carefully).