Well, it will be a bit of a challenge without betraying commercial confidentialities, which I'm not about to do (after all, we hardly know each other - blush). I know of many of these incidents as a result of being involved in the upgrading of their fire alarm systems in accordance with the terms of the DRC's requirements.
You could try a Google search under the Disability Rights Commission's archives, but I suspect it's a long process and I've no idea whether they publicised many of the instances, most of which were settled before coming to court. The DRC was notoriously litigious however. Most organisations chose to simply carry out their required amendments, as the DRC tended to win far more often than it lost apparently and it wasn't worth arguing the toss with them. I believe I'm right in saying the courtroom incident I referred to was in Winchester.
The salient point here however is this. The OP is entirely correct to question his employers adjustments to allow equal access to goods and services. If he feels that the response is inadequate, he is able to call in the E&HRC to get their opinion. If no adjustment has been made to the fire alarm system, as would be required under BS5839, then they would take that up with the employer. It is not sufficient to simply say that it will be addresed the next time the fire alarm needs changing, or when there's a building refurbishment. The DDA is law and it's implications are current, it cannot be ignored until a more convenient time.
What is more, the company servicing the fire alarm system should be advising on any changes to the buildig structure or usage which may affect compliance with BS5839 (see section 18). If there is no provision for disabled users then this should be noted as part of that process and the client should address this if any users require access to it.
If the building is a 'public access' building, such as a library, or town hall, then the DDA 2005 - The Disability Equality Duty, puts further obligations onto such employers and service providers (although a supermarket is not covered by this piece of legislation).