I was not at the Flyer show, so I'll have to take your word for what those presenters said. However, BA are not recruiting low-hour pilots and will not be for some time to come, so why they should have an opinion on this isn't clear to me. DHL and Astraeus may do so, but in very small numbers. It may be that they take some note of which school their interviewees went to, but I seriously doubt that they would reject a good, properly qualified prospect on the basis of which school they attended.
All schools offering CAA/JAA training are audited by the CAA to ensure that their training is up to standard. The skills tests and ratings are administered by CAA-appointed examiners to a fixed schedule with well-understood minimum requirements for achieving a pass. That is why it is the qualification, not the school, which is important to the employer.
However, it is certainly true that schools vary in the standards of the overall package they deliver to you, the customer, and that you should choose carefully to whom you give your cash.
Scroggs