CRB clearance is only required for jobs with children and vulnerable adults and certain positions involving security (airside pass). If the job does not fall into this category the employer has no right to even mention it and cant check anything without your written consent. They are also not allowed to turn you down for a job for any non-relevant convictions. web sites are full of jobs that fall under categorys for a CRB check and there is no way an FI falls into this category.
thanks