Understand, as I am sure you do, that the law is a very complicated process. In the UK there are three types of bail:
1. Police Bail where a suspect is released without being charged but must return to the police station at a given time.
2. Police to Court where having been charged a suspect is given bail but must attend his first court hearing at the time and Court given
3. Court bail where having already been in court a suspect is granted bail pending further investigation or while the case continues.
While the parameters for granting bail vary according to the severity of the offence (a suspected murderer is rarely granted bail by the police or the courts) the likelihood of re-offending is also taken into consideration. While the police may consider you are likely to re-offend because you have been arrested and charged but not found guilty for numerous previous similar offences, and so refuse bail, the courts must normally consider each appearance as a separate offence (you are charged with the offence of theft, not of being a thief) and so may be more inclined, or perhaps (and I have no expertise in this field) legally obliged to consider bail.
This might explain why courts look for substantial grounds (there have been previous arrests but no convictions and legally the defendant is to be considered innocent until found guilty) and the police look for reasonable grounds (there have been previous arrests but no convictions and while considered innocent until found guilty �it is believed further offences may committed while on bail�). It is, therefore the interpretation of the officers of the law as to the suitability or otherwise that bail should be considered.