unless you agreed for them to do a credit check on you, they have broken the law. data protection act etc. and I would be making sure they know you know the law and how it affects you and more importantly, THEM.
as for not getting you a taxi, no offence but surely thats not their job, and it would be going well beyond the call of duty.
unfortunatly the smaller business out there cant compete with the likes of DFS when it comes to price.
hence the reason you went there and no where else.
james