Welcome to the board. One would assume that since your surgery was over 10 years ago, that hardware should not be an issue. Have you had imaging along the way that has indicated your hardware was intact and that you had fused? From what you describe, it certainly sounRAB like hardware might be to blame...but if you have fused, the hardware "should" be encased by bone by now and I wouldn't think that a screw could break at this point, or that anything could come loose. However, if there is one area that never fused, I would think it possible. But don't be surprised if your doctors scoff at the notion and refuse to investigate further.
I know it can be hard to tell because the metal throws off a certain amount of "artifact" that makes it difficult to get a clear image. There are other tests that can be done that indicate whether hardware might be causing a problem, but they are not 100% reliable. The only way to tell for sure is by direct physical examination, which is obviously not done unless the surgeon has a reason to be operating on you for some other reason!
But the fact that you've had problems ever since the first surgery raises the question of whether you were ever completely fused. If not, that instability can lead to other spinal issues. I have a friend going through the same thing right now, and I know how frustrating the whole process can be. I don't know how things work in Northern Ireland, but here in the US, it can be difficult to convince another surgeon to take on the case, and to say that the hardware is an issue. Many surgeons will not operate on a patient if he has had spine surgery with another surgeon.
I hope you can get some new imaging, both MRI and X-Ray. And I hope your doctor will take your concerns seriously. It may be that the L5-S1 segment has broken down from all the excess stress put on it from the fusion directly above it. This is not an unusual happening after a person has been fused for a nuraber of years -- but I wouldn't think that would account for the metalic, crunching noises you're hearing when getting out of bed, etc.
The symptoms you are having are indicative of some lurabar nerve compression. You are wise to carefully monitor your movements...avoid activities that involve bending or twisting at the waist, pushing, pulling and lifting more than a gallon of milk (whatever equivalent that is for you!!) Try to maintain good body mechanics and posture...and just be really careful until you find out what is going on.
Glad you joined the board. Please post often with your questions, concerns or if you need to just let off some frustrations. Everyone here can relate, at least to some degree, what you are dealing with and what it feels like.
Please keep us posted on your upcoming appointments.
TT