I would think any " serious " conviction would be taken into account especialy if it involved physical behavour of the assult type " for this type of job". I am not in the know of the law on this but comon sence would tell me that . I am taking it that "sentence ended 2004" would mean what ever term they impossed as punishment, i understand that convictions passed 7 years should not be recalled but i would double check if this is after the end of " said " conviction end term or the conviction date as it would not seem propper for a 15 year jail sentance to be unmensionable after its 7th year of sentance. best advice i can offer is ask at local police station they should be able to answer that one , if that fails talk to a lawyer many do inicial free consultations.
Not sure if this would be helpful or not , but felt you deserved a responce