The Police, in order to make ANY arrest, must have what in law is known as "reasonable grounds for suspicion" and boils down to whether or not the arrest, as per the law, was both lawful and necessary. However, that has to be tempered with a number of factors. Take a look at these links:
http://www.wikicrimel...title=Power_of_arrest
http://sixthformlaw.i..._powers_of_arrest.htm
Therefore, it will depend to an extent as to whether or not the landlord, Mr Jefferies, has any further action taken against him. He is presently still on Bail as far as I'm aware. Should he "answer his Bail", as it is know, i.e. return to whichever Police Station it is on the date his Bail expires, or should he be informed prior to that, that nothing else will be proceeded against him, then he may feel free to seek legal advice as to whether he might consider suing the Police for possible wrongful arrest.
If, however, he were to be charged, and subsequently convicted of any offence, he'd be on a fairly shaky peg. It all depends.